The autonomic nervous system (ANS), sometimes called the visceral nervous system and formerly the vegetative nervous system, is a division of the nervous system that operates internal organs, smooth muscle and glands. The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, its force of contraction, digestion, respiratory rate, pupillary response, urination, and sexual arousal. The fight-or-flight response, also known as the acute stress response, is set into action by the autonomic nervous system.
Although conflicting reports about its subdivisions exist in the
literature, the autonomic nervous system has historically been
considered a purely motor system, and has been divided into three
branches: the sympathetic nervous system, the parasympathetic nervous system, and the enteric nervous system. Some textbooks do not include the enteric nervous system as part of this system. The sympathetic nervous system is responsible for setting off the fight-or-flight response. The parasympathetic nervous system is responsible for the body's rest and digestion response.
In many cases, both of these systems have "opposite" actions where one
system activates a physiological response and the other inhibits it. An
older simplification of the sympathetic and parasympathetic nervous
systems as "excitatory" and "inhibitory" was overturned due to the many
exceptions found. A more modern characterization is that the sympathetic
nervous system is a "quick response mobilizing system" and the
parasympathetic is a "more slowly activated dampening system", but even this has exceptions, such as in sexual arousal and orgasm, wherein both play a role.
There are inhibitory and excitatorysynapses between neurons. A third subsystem of neurons has been named as non-noradrenergic, non-cholinergic transmitters (because they use nitric oxide as a neurotransmitter) and are integral in autonomic function, in particular in the gut and the lungs.though the ANS is also known as the visceral nervous system and
although most of its fibers carry non-somatic information to the CNS,
many authors still consider it only connected with the motor side. Most autonomous functions are involuntary but they can often work in conjunction with the somatic nervous system which provides voluntary control.
Structure
Autonomic nervous system, showing splanchnic nerves in middle, and the vagus nerve as "X" in blue. The heart and organs below in list to right are regarded as viscera.
The autonomic nervous system is unique in that it requires a
sequential two-neuron efferent pathway; the preganglionic neuron must
first synapse onto a postganglionic neuron before innervating the target
organ. The preganglionic, or first, neuron will begin at the "outflow"
and will synapse at the postganglionic, or second, neuron's cell body.
The postganglionic neuron will then synapse at the target organ.
The sympathetic nervous system consists of cells with bodies in the lateral grey column from T1 to L2/3. These cell bodies are "GVE" (general visceral efferent) neurons
and are the preganglionic neurons. There are several locations upon
which preganglionic neurons can synapse for their postganglionic
neurons:
paravertebral ganglia (3) of the sympathetic chain (these run on either side of the vertebral bodies)
chromaffin cells of the adrenal medulla (this is the one exception to the two-neuron pathway rule: the synapse is directly efferent onto the target cell bodies)
These ganglia provide the postganglionic neurons from which innervation of target organs follows. Examples of splanchnic (visceral) nerves are:
cervical cardiac nerves and thoracic visceral nerves, which synapse in the sympathetic chain
The parasympathetic nervous system consists of cells with bodies in one of two locations: the brainstem
(cranial nerves III, VII, IX, X) or the sacral spinal cord (S2, S3,
S4). These are the preganglionic neurons, which synapse with
postganglionic neurons in these locations:
The
intricate process of enteric nervous system (ENS) development begins
with the migration of cells from the vagal section of the neural crest.
These cells embark on a journey from the cranial region to populate the
entire gastrointestinal tract. Concurrently, the sacral section of the
neural crest provides an additional layer of complexity by contributing
input to the hindgut ganglia. Throughout this developmental journey,
numerous receptors exhibiting tyrosine kinase activity, such as Ret and
Kit, play indispensable roles. Ret, for instance, plays a critical role
in the formation of enteric ganglia derived from cells known as vagal
neural crest. In mice, targeted disruption of the RET gene results in
renal agenesis and the absence of enteric ganglia, while in humans,
mutations in the RET gene are associated with megacolon. Similarly, Kit,
another receptor with tyrosine kinase activity, is implicated in Cajal
interstitial cell formation, influencing the spontaneous, rhythmic,
electrical excitatory activity known as slow waves in the
gastrointestinal tract. Understanding the molecular intricacies of these
receptors provides crucial insights into the delicate orchestration of
ENS development.
Structure of the enteric nervous system
The
structural complexity of the enteric nervous system (ENS) is a
fascinating aspect of its functional significance. Originally perceived
as postganglionic parasympathetic neurons, the ENS earned recognition
for its autonomy in the early 1900s. Boasting approximately 100 million
neurons, a quantity comparable to the spinal cord, the ENS is often
described as a "brain of its own." This description is rooted in the
ENS's ability to communicate independently with the central nervous
system through parasympathetic and sympathetic neurons. At the core of
this intricate structure are the myenteric plexus (Auerbach's) and the
submucous plexus (Meissner's), two main plexuses formed by the grouping
of nerve-cell bodies into tiny ganglia connected by bundles of nerve
processes. The myenteric plexus extends the full length of the gut,
situated between the circular and longitudinal muscle layers. Beyond its
primary motor and secretomotor functions, the myenteric plexus exhibits
projections to submucosal ganglia and enteric ganglia in the pancreas
and gallbladder, showcasing the interconnectivity within the ENS.
Additionally, the myenteric plexus plays a unique role in innervating
motor end plates with the inhibitory neurotransmitter nitric oxide in
the striated-muscle segment of the esophagus, a feature exclusive to
this organ. Meanwhile, the submucous plexus, most developed in the small
intestine, occupies a crucial position in secretory regulation.
Positioned in the submucosa between the circular muscle layer and the
muscularis mucosa, the submucous plexus's neurons innervate intestinal
endocrine cells, submucosal blood arteries, and the muscularis mucosa,
emphasizing its multifaceted role in gastrointestinal function.
Furthermore, ganglionated plexuses in the pancreatic, cystic duct,
common bile duct, and gallbladder, resembling submucous plexuses,
contribute to the overall complexity of the ENS structure. In this
intricate landscape, glial cells emerge as key players, outnumbering
enteric neurons and covering the majority of the surface of enteric
neuronal-cell bodies with laminar extensions. Resembling the astrocytes
of the central nervous system, enteric glial cells respond to cytokines
by expressing MHC class II antigens and generating interleukins. This
underlines their pivotal role in modulating inflammatory responses in
the intestine, adding another layer of sophistication to the functional
dynamics of the ENS. The varied morphological shapes of enteric neurons
further contribute to the structural diversity of the ENS, with neurons
capable of exhibiting up to eight different morphologies. These neurons
are primarily categorized into type I and type II, where type II neurons
are multipolar with numerous long, smooth processes, and type I neurons
feature numerous club-shaped processes along with a single long,
slender process. The rich structural diversity of enteric neurons
highlights the complexity and adaptability of the ENS in orchestrating a
wide array of gastrointestinal functions, reflecting its status as a
dynamic and sophisticated component of the nervous system.
The visceral sensory system - technically not a part of the autonomic
nervous system - is composed of primary neurons located in cranial
sensory ganglia: the geniculate, petrosal and nodose ganglia, appended respectively to cranial nerves VII, IX and X. These sensory neurons monitor the levels of carbon dioxide, oxygen
and sugar in the blood, arterial pressure and the chemical composition
of the stomach and gut content. They also convey the sense of taste and
smell, which, unlike most functions of the ANS, is a conscious
perception. Blood oxygen and carbon dioxide are in fact directly sensed
by the carotid body, a small collection of chemosensors at the
bifurcation of the carotid artery, innervated by the petrosal (IXth)
ganglion.
Primary sensory neurons project (synapse) onto "second order" visceral
sensory neurons located in the medulla oblongata, forming the nucleus of the solitary tract
(nTS), that integrates all visceral information. The nTS also receives
input from a nearby chemosensory center, the area postrema, that detects
toxins in the blood and the cerebrospinal fluid and is essential for
chemically induced vomiting or conditional taste aversion (the memory
that ensures that an animal that has been poisoned by a food never
touches it again). All this visceral sensory information constantly and
unconsciously modulates the activity of the motor neurons of the ANS.
Innervation
Autonomic nerves travel to organs throughout the body. Most organs receive parasympathetic supply by the vagus nerve and sympathetic supply by splanchnic nerves. The sensory part of the latter reaches the spinal column at certain spinal segments. Pain in any internal organ is perceived as referred pain, more specifically as pain from the dermatome corresponding to the spinal segment.
Autonomic nervous system's jurisdiction to organs in the human bodyedit
Motor neurons of the autonomic nervous system are found in "autonomic
ganglia". Those of the parasympathetic branch are located close to the
target organ whilst the ganglia of the sympathetic branch are located
close to the spinal cord.
The sympathetic ganglia here, are found in two chains: the
pre-vertebral and pre-aortic chains. The activity of autonomic
ganglionic neurons is modulated by "preganglionic neurons" located in
the central nervous system. Preganglionic sympathetic neurons are
located in the spinal cord, at the thorax and upper lumbar levels.
Preganglionic parasympathetic neurons are found in the medulla oblongata
where they form visceral motor nuclei; the dorsal motor nucleus of the
vagus nerve; the nucleus ambiguus, the salivatory nuclei, and in the sacral region of the spinal cord.
Function
Function of the autonomic nervous system
Sympathetic and parasympathetic divisions typically function in
opposition to each other. But this opposition is better termed
complementary in nature rather than antagonistic. For an analogy, one
may think of the sympathetic division as the accelerator and the
parasympathetic division as the brake. The sympathetic division
typically functions in actions requiring quick responses. The
parasympathetic division functions with actions that do not require
immediate reaction. The sympathetic system is often considered the "fight or flight" system, while the parasympathetic system is often considered the "rest and digest" or "feed and breed" system.
However, many instances of sympathetic and parasympathetic
activity cannot be ascribed to "fight" or "rest" situations. For
example, standing up from a reclining or sitting position would entail
an unsustainable drop in blood pressure if not for a compensatory
increase in the arterial sympathetic tonus. Another example is the
constant, second-to-second, modulation of heart rate by sympathetic and
parasympathetic influences, as a function of the respiratory cycles. In
general, these two systems should be seen as permanently modulating
vital functions, in a usually antagonistic fashion, to achieve homeostasis.
Higher organisms maintain their integrity via homeostasis which relies
on negative feedback regulation which, in turn, typically depends on the
autonomic nervous system. Some typical actions of the sympathetic and parasympathetic nervous systems are listed below.
Target organ/system
Parasympathetic
Sympathetic
Digestive system
Increase peristalsis and amount of secretion by digestive glands
Decrease activity of digestive system
Liver
No effect
Causes glucose to be released to blood
Lungs
Constricts bronchioles
Dilates bronchioles
Urinary bladder and Urethra
Relaxes sphincter
Constricts sphincter
Kidneys
No effects
Decrease urine output
Heart
Decreases rate
Increase rate
Blood vessels
No effect on most blood vessels
Constricts blood vessels in viscera; increase BP
Salivary and lacrimal glands
Stimulates; increases production of saliva and tears
Inhibits; result in dry mouth and dry eyes
Eye (iris)
Stimulates constrictor muscles; constrict pupils
Stimulate dilator muscle; dilates pupils
Eye (ciliary muscles)
Stimulates to increase bulging of lens for close vision
Inhibits; decrease bulging of lens; prepares for distant vision
Adrenal medulla
No effect
Stimulate medulla cells to secrete epinephrine and norepinephrine
Sweat gland of skin
No effect
Stimulate sudomotor function to produce perspiration
The parasympathetic nervous system has been said to promote a "rest
and digest" response, promotes calming of the nerves return to regular
function, and enhancing digestion. Functions of nerves within the
parasympathetic nervous system include:
Dilating blood vessels leading to the GI tract, increasing the blood flow.
Constricting the bronchiolar diameter when the need for oxygen has diminished
Constriction of the pupil and contraction of the ciliary muscles, facilitating accommodation and allowing for closer vision
Stimulating salivary gland secretion, and accelerates peristalsis, mediating digestion of food and, indirectly, the absorption of nutrients
Sexual. Nerves of the peripheral nervous system are involved in the erection of genital tissues via the pelvic splanchnic nerves 2–4. They are also responsible for stimulating sexual arousal.
The enteric nervous system is the intrinsic nervous system of the gastrointestinal system. It has been described as the "second brain of the human body". Its functions include:
Sensing chemical and mechanical changes in the gut
A
flow diagram showing the process of stimulation of adrenal medulla that
makes it release adrenaline, that further acts on adrenoreceptors,
indirectly mediating or mimicking sympathetic activity
Acetylcholine
is the preganglionic neurotransmitter for both divisions of the ANS, as
well as the postganglionic neurotransmitter of parasympathetic neurons.
Nerves that release acetylcholine are said to be cholinergic. In the
parasympathetic system, ganglionic neurons use acetylcholine as a
neurotransmitter to stimulate muscarinic receptors.
At the adrenal medulla, there is no postsynaptic neuron. Instead, the presynaptic neuron releases acetylcholine to act on nicotinic receptors. Stimulation of the adrenal medulla releases adrenaline
(epinephrine) into the bloodstream, which acts on adrenoceptors,
thereby indirectly mediating or mimicking sympathetic activity.
Recent
studies indicate that ANS activation is critical for regulating the
local and systemic immune-inflammatory responses and may influence acute
stroke outcomes. Therapeutic approaches modulating the activation of
the ANS or the immune-inflammatory response could promote neurologic
recovery after stroke.
History
The specialised system of the autonomic nervous system was recognised by Galen.
In 1665, Thomas Willis used the terminology, and in 1900, John Newport Langley used the term, defining the two divisions as the sympathetic and parasympathetic nervous systems.
Caffeine effects
Caffeine is a bioactive ingredient
found in commonly consumed beverages such as coffee, tea, and sodas.
Short-term physiological effects of caffeine include increased blood pressure
and sympathetic nerve outflow. Habitual consumption of caffeine may
inhibit physiological short-term effects. Consumption of caffeinated
espresso increases parasympathetic activity in habitual caffeine
consumers; however, decaffeinated espresso inhibits parasympathetic
activity in habitual caffeine consumers. It is possible that other
bioactive ingredients in decaffeinated espresso may also contribute to
the inhibition of parasympathetic activity in habitual caffeine
consumers.
Caffeine is capable of increasing work capacity while individuals
perform strenuous tasks. In one study, caffeine provoked a greater
maximum heart rate while a strenuous task was being performed compared to a placebo.
This tendency is likely due to caffeine's ability to increase
sympathetic nerve outflow. Furthermore, this study found that recovery
after intense exercise was slower when caffeine was consumed prior to
exercise. This finding is indicative of caffeine's tendency to inhibit
parasympathetic activity in non-habitual consumers. The
caffeine-stimulated increase in nerve activity is likely to evoke other
physiological effects as the body attempts to maintain homeostasis.
The effects of caffeine on parasympathetic activity may vary
depending on the position of the individual when autonomic responses are
measured. One study found that the seated position inhibited autonomic
activity after caffeine consumption (75 mg); however, parasympathetic
activity increased in the supine position. This finding may explain why
some habitual caffeine consumers (75 mg or less) do not experience
short-term effects of caffeine if their routine requires many hours in a
seated position. It is important to note that the data supporting
increased parasympathetic activity in the supine position was derived
from an experiment involving participants between the ages of 25 and 30
who were considered healthy and sedentary. Caffeine may influence
autonomic activity differently for individuals who are more active or
elderly.
Addiction is a neuropsychologicaldisorder characterized by a persistent and intense urge to use a drug
or engage in a behavior that produces natural reward, despite
substantial harm and other negative consequences. Repetitive drug use
can alter brain function in synapses similar to natural rewards like food or falling in love in ways that perpetuate craving and weakens self-control for people with pre-existing vulnerabilities. This phenomenon – drugs reshapingbrain function – has led to an understanding of addiction as a brain disorder with a complex variety of psychosocial as well as neurobiological factors that are implicated in the development of addiction. While mice given cocaine showed the compulsive and involuntary nature of addiction, for humans this is more complex, related to behavior or personality traits.
Classic signs of addiction include compulsive engagement in rewarding stimuli, preoccupation with substances or behavior, and continued use despite negative consequences. Habits and patterns associated with addiction are typically characterized by immediate gratification (short-term reward), coupled with delayed deleterious effects (long-term costs).
Signs and symptoms of drug addiction can vary depending on the type of addiction. Symptoms may include:
Continuation of drug use despite the knowledge of consequences
Disregarding financial status when it comes to drug purchases
Ensuring a stable supply of the drug
Needing more of the drug over time to achieve similar effects
Social and work life impacted due to drug use
Unsuccessful attempts to stop drug use
Urge to use drug regularly
Other signs and symptoms can be categorized across relevant dimensions:
Behavioral Changes
Physical Changes
Social Changes
Angry and irritable
Changes to eating or sleeping habits
Changes to personality and attitude
Decreased attendance and performance in workplace or school setting
Fearful, paranoid and anxious without probable cause
Frequently engaging in conflicts (fights, illegal activity)
Frequent or sudden changes in mood and temperament
Hiding or in denial of certain behaviors
Lack of motivation
Periodic hyperactivity
Using substances in inappropriate settings
Abnormal pupil size
Bloodshot eyes
Body odor
Impaired motor coordination
Periodic tremors
Poor physical appearance
Slurred speech
Sudden changes in weight
Changes in hobbies
Changes to financial status (unexplained need for money)
Legal problems related to substance abuse
Sudden changes in friends and associates
Use of substance despite consequences to personal relationships
Definitions
The word "addiction" derives from the Latin "addico", meaning "giving over" with both positive connotations (devotion, dedication) and negative ones (being enslaved to a creditor in Roman law).
This dual meaning persisted in traditional English dictionaries,
encompassing both legal surrender and personal devotion to habits.
Later, 19th century temperance movements
narrowed the definition of addiction to just drug-related disease,
ignoring behavioral addictions and the possibility of positive or
neutral addictions. This restrictive view opposes the current
understanding of addiction.
"Addiction" and "addictive behaviour" are polysemes denoting a category of mental disorders, of neuropsychological symptoms, or of merely maladaptive/harmful habits and lifestyles.
A common use of "addiction" in medicine is for neuropsychological
symptoms denoting pervasive/excessive and intense urges to engage in a
category of behavioral compulsions or impulses towards sensory rewards (e.g., alcohol, betel quid, drugs, sex, gambling, video gaming). Addictive disorders or addiction disorders are mental disorders involving high intensities of addictions (as neuropsychological symptoms) that induce functional disabilities (i.e., limit subjects' social/family and occupational activities); the two categories of such disorders are substance-use addictions and behavioral addictions.
The DSM-5
classifies addiction the most severe stage of substance use disorder,
due to significant loss of control and the presence of compulsive
behaviours despite the desire to stop. It is a definition that many scientific papers and reports use.
"Dependence" is also a polyseme denoting either
neuropsychological symptoms or mental disorders. In the DSM-5,
dependences differ from addictions and can even normally happen without
addictions; besides, substance-use dependences are severe stages of substance-use addictions (i.e. mental disorders) involving withdrawal issues.
In the ICD-11, "substance-use dependence" is a synonym of
"substance-use addiction" (i.e. neuropsychological symptoms) that can
but do not necessarily involve withdrawal issues.
addiction – a biopsychosocial disorder characterized by persistent use of drugs (including alcohol) despite substantial harm and adverse consequences
addictive drug –
psychoactive substances that with repeated use are associated with
significantly higher rates of substance use disorders, due in large part
to the drug's effect on brain reward systems
dependence – an adaptive state associated with a withdrawal syndrome upon cessation of repeated exposure to a stimulus (e.g., drug intake)
drug sensitization or reverse tolerance – the escalating effect of a drug resulting from repeated administration at a given dose
drug withdrawal – symptoms that occur upon cessation of repeated drug use
psychological dependence
– dependence socially seen as being extremely mild compared to physical
dependence (e.g., with enough willpower it could be overcome)
reinforcing stimuli – stimuli that increase the probability of repeating behaviors paired with them
rewarding stimuli – stimuli that the brain interprets as intrinsically positive and desirable or as something to approach
sensitization – an amplified response to a stimulus resulting from repeated exposure to it
substance use disorder – a condition in which the use of substances leads to clinically and functionally significant impairment or distress
tolerance – the diminishing effect of a drug resulting from repeated administration at a given dose
Drug addiction
Drug addiction, which belongs to the class of substance-related disorders, is a chronic and relapsing brain disorder that features drug seeking and drug abuse, despite their harmful effects. This form of addiction changes brain circuitry such that the brain's reward system is compromised, causing functional consequences for stress management and self-control. Damage to the functions of the organs involved can persist throughout a lifetime and cause death if untreated.
Substances involved with drug addiction include alcohol, nicotine,
marijuana, opioids, cocaine, amphetamines, and even foods with high fat
and sugar content. Addictions can begin experimentally in social contexts and can arise from the use of prescribed medications or a variety of other measures.
Drug addiction has been shown to work in phenomenological, conditioning (operant and classical), cognitive models, and the cue reactivity model. However, no one model completely illustrates substance abuse.
The diagnostic criteria for food or eating addiction has not been categorized or defined in references such as the Diagnostic and Statistical Manual of Mental Disorders (DSM or DSM-5) and is based on subjective experiences similar to substance use disorders.
Food addiction may be found in those with eating disorders, though not
all people with eating disorders have food addiction and not all of
those with food addiction have a diagnosed eating disorder. Long-term frequent and excessive consumption of foods high in fat, salt, or sugar, such as chocolate, can produce an addictionsimilar to drugs since they trigger the brain's reward system, such
that the individual may desire the same foods to an increasing degree
over time.
The signals sent when consuming highly palatable foods have the ability
to counteract the body's signals for fullness and persistent cravings
will result.
Those who show signs of food addiction may develop food tolerances, in
which they eat more, despite the food becoming less satisfactory.
Chocolate's sweet flavor and pharmacological ingredients are
known to create a strong craving or feel 'addictive' by the consumer. A person who has a strong liking for chocolate may refer to themselves as a chocoholic.
Risk factors for developing food addiction include excessive overeating and impulsivity.
The Yale Food Addiction Scale
(YFAS), version 2.0, is the current standard measure for assessing
whether an individual exhibits signs and symptoms of food addiction. It was developed in 2009 at Yale University
on the hypothesis that foods high in fat, sugar, and salt have
addictive-like effects which contribute to problematic eating habits.
The YFAS is designed to address 11 substance-related and addictive
disorders (SRADs) using a 25-item self-report questionnaire, based on
the diagnostic criteria for SRADs as per DSM-5.
A potential food addiction diagnosis is predicted by the presence of at
least two out of 11 SRADs and a significant impairment to daily
activities.
The term behavioral addiction refers to a compulsion to engage in a natural reward – which is a behavior that is inherently rewarding (i.e., desirable or appealing) – despite adverse consequences. Preclinical evidence has demonstrated that marked increases in the expression of ΔFosB through repetitive and excessive exposure to a natural reward induces the same behavioral effects and neuroplasticity as occurs in a drug addiction.
Addiction can exist without psychotropic drugs, an idea that was popularized by psychologist Stanton Peele.
These are termed behavioral addictions. Such addictions may be passive
or active, but they commonly contain reinforcing features, which are
found in most addictions.
Sexual behavior, eating, gambling, playing video games, and shopping
are all associated with compulsive behaviors in humans and have been
shown to activate the mesolimbic pathway and other parts of the reward
system. Based on this evidence, sexual addiction, gambling addiction, video game addiction, and shopping addiction are classified accordingly.
Sexual
Sexual addiction is a state characterized by compulsive participation or engagement in sexual activity, particularly sexual intercourse, despite negative consequences. The concept is contentious; as of 2023, sexual addiction is not a clinical diagnosis in either the DSM or ICD medical classifications of diseases and medical disorders, which instead categorize such behaviors under labels such as compulsive sexual behavior.
There is considerable debate among psychiatrists, psychologists, sexologists, and other specialists whether compulsive sexual behavior constitutes an addiction – in this instance a behavioral addiction – and therefore its classification and possible diagnosis. Animal research has established that compulsive sexual behavior arises from the same transcriptional and epigenetic mechanisms that mediate drug addiction
in laboratory animals. Some argue that applying such concepts to normal
behaviors such as sex can be problematic, and suggest that applying
medical models such as addiction to human sexuality can serve to
pathologise normal behavior and cause harm.
Gambling provides a natural reward that is associated with compulsive behavior. Functional neuroimaging evidence shows that gambling activates the reward system and the mesolimbic pathway in particular. It is known that dopamine is involved in learning, motivation, as well as the reward system. The exact role of dopamine in gambling addiction has been debated. Suggested roles for D2, D3, and D4dopamine receptors, as well as D3 receptors in the substantia nigra have been found in rat and human models, showing a correlation with the severity of the gambling behavior. This in turn was linked with greater dopamine release in the dorsal striatum.
Risk factors for gambling addictions include antisocial behavior, impulsive personality, male sex, sensation seeking, substance use, and young age.
Gambling addiction has been associated with some personality
traits, including: harm avoidance, low self direction, decision making
and planning insufficiencies, impulsivity, as well as sensation seeking
individuals.
Although some personality traits can be linked with gambling addiction,
there is no general description of individuals addicted to gambling.
Internet addiction does not have any standardized definition, yet there is widespread agreement that this problem exists.
Debate over the classification of problematic internet use considers
whether it should be thought of as a behavioral addiction, an impulse
control disorder, or an obsessive-compulsive disorder.
Others argue that internet addiction should be considered a symptom of
an underlying mental health condition and not a disorder in itself.
Internet addiction has been described as "a psychological dependence on
the Internet, regardless of the type of activity once logged on."
Problematic internet use may include a preoccupation with the internet
and/or digital media, excessive time spent using the internet despite
resultant distress in the individual, increase in the amount of internet
use required to achieve the same desired emotional response, loss of
control over one's internet use habits, withdrawal symptoms, and
continued problematic internet use despite negative consequences to
one's work, social, academic, or personal life.
Studies conducted in India, United States, Asia, and Europe have
identified Internet addiction prevalence rates ranging in value from 1%
to 19%, with the adolescent population having high rates compared to
other age groups.
Prevalence rates have been difficult to establish due to a lack of
universally accepted diagnostic criteria, a lack of diagnostic
instruments demonstrating cross-cultural validity and reliability, and
existing controversy surrounding the validity of labeling problematic
internet use as an addictive disorder. The most common scale used to measure addiction is the Internet Addiction Test developed by Kimberly Young.
People with internet addiction are likely to have a comorbid
psychiatric disorder. Comorbid diagnoses identified alongside internet
addiction include affective mood disorders, anxiety disorders, substance
use disorders, and attention deficit hyperactivity disorder.
Video game addiction is characterized by the World Health Organization
(WHO) as excessive gaming behavior, potentially prioritized over other
interests, despite the negative consequences that may arise, for a
period of at least 12 months. In May 2019, the WHO introduced gaming disorder in the 11th edition of the International Classification of Diseases. Video game addiction has been shown to be more prevalent in males than females, higher by 2.9 times. It has been suggested that people of younger ages are more prone to become addicted to video games. People with certain personalities may be more susceptible to gaming addictions.
Shopping addiction, or compulsive buying disorder (CBD), is the excessive urge to shop or spend, potentially resulting in unwanted consequences. These consequences can have serious impacts, such as increased consumer debt, negatively affected relationships, increased risk of illegal behavior, and suicide attempts. Shopping addiction occurs worldwide and has shown a 5.8% prevalence in the United States.
Similar to other behavioral addictions, CBD can be linked to mood
disorders, substance use disorders, eating disorders, and other
disorders involving a lack of control.
Screening and assessment
Addictions Neuroclinical Assessment
The Addictions Neuroclinical Assessment is used to diagnose addiction disorders. This tool measures three different domains: executive function, incentive salience, and negative emotionality.Executive functioning consists of processes that would be disrupted in addiction. In the context of addiction, incentive salience determines how one perceives the addictive substance. Increased negative emotional responses have been found with individuals with addictions.
Tobacco, Alcohol, Prescription Medication, and Other Substance Use (TAPS)
This
is a screening and assessment tool in one, assessing commonly used
substances. This tool allows for a simple diagnosis, eliminating the
need for several screening and assessment tools, as it includes both
TAPS-1 and TAPS-2, screening and assessment tools respectively. The
screening component asks about the frequency of use of the specific
substance (tobacco, alcohol, prescription medication, and other). If an individual screens positive, the second component will begin. This dictates the risk level of the substance.
CRAFFT
The
CRAFFT (Car-Relax-Alone-Forget-Family and Friends-Trouble) is a
screening tool that is used in medical centers. The CRAFFT is in version
2.1 and has a version for nicotine and tobacco use called the CRAFFT
2.1+N.
This tool is used to identify substance use, substance related driving
risk, and addictions among adolescents. This tool uses a set of
questions for different scenarios.
In the case of a specific combination of answers, different question
sets can be used to yield a more accurate answer. After the questions,
the DSM-5 criteria are used to identify the likelihood of the person
having substance use disorder. After these tests are done, the clinician is to give the "5 RS" of brief counseling.
The five Rs of brief counseling includes:
REVIEW screening results
RECOMMEND to not use
RIDING/DRIVING risk counseling
RESPONSE: elicit self-motivational statements
REINFORCE self-efficacy
Drug Abuse Screening Test (DAST-10)
The Drug Abuse Screening Test (DAST) is a self-reporting tool that measures problematic substance use.
Responses to this test are recorded as yes or no answers, and scored as
a number between zero and 28. Drug abuse or dependence, are indicated
by a cut off score of 6.
Three versions of this screening tool are in use: DAST-28, DAST-20, and
DAST-10. Each of these instruments are copyrighted by Dr. Harvey A.
Skinner.
Alcohol, Smoking, and Substance Involvement Test (ASSIST)
The
Alcohol, Smoking, and Substance Involvement Test (ASSIST) is an
interview-based questionnaire consisting of eight questions developed by
the WHO.
The questions ask about lifetime use; frequency of use; urge to use;
frequency of health, financial, social, or legal problems related to
use; failure to perform duties; if anyone has raised concerns over use;
attempts to limit or moderate use; and use by injection.
The transtheoretical model
of change (TTM) can point to how someone may be conceptualizing their
addiction and the thoughts around it, including not being aware of their
addiction.
In operant conditioning, behavior is influenced by outside stimulus,
such as a drug. The operant conditioning theory of learning is useful in
understanding why the mood-altering or stimulating consequences of drug
use can reinforce continued use (an example of positive reinforcement) and why the addicted person seeks to avoid withdrawal through continued use (an example of negative reinforcement). Stimulus control is using the absence of the stimulus or presence of a reward to influence the resulting behavior.
Cognitive control is the intentional selection of thoughts,
behaviors, and emotions, based on our environment. It has been shown
that drugs alter the way our brains function, and its structure.Cognitive functions such as learning, memory, and impulse control, are affected by drugs. These effects promote drug use, as well as hinder the ability to abstain from it. The increase in dopamine release is prominent in drug use, specifically in the ventral striatum and the nucleus accumbens.
Dopamine is responsible for producing pleasurable feelings, as well
driving us to perform important life activities. Addictive drugs cause a
significant increase in this reward system, causing a large increase in
dopamine signaling as well as increase in reward-seeking behavior, in
turn motivating drug use. This promotes the development of a maladaptive drug to stimulus relationship.
Early drug use leads to these maladaptive associations, later affecting
cognitive processes used for coping, which are needed to successfully
abstain from them.
A number of genetic and environmental risk factors exist for developing an addiction. Genetic and environmental risk factors each account for roughly half of an individual's risk for developing an addiction; the contribution from epigenetic risk factors to the total risk is unknown.
Even in individuals with a relatively low genetic risk, exposure to
sufficiently high doses of an addictive drug for a long period of time
(e.g., weeks–months) can result in an addiction.
Adverse childhood events are associated with negative health outcomes,
such as substance use disorder. Childhood abuse or exposure to violent
crime is related to developing a mood or anxiety disorder, as well as a
substance dependence risk.
Genetic factors, along with socio-environmental (e.g., psychosocial) factors, have been established as significant contributors to addiction vulnerability.
Studies done on 350 hospitalized drug-dependent patients showed that
over half met the criteria for alcohol abuse, with a role of familial
factors being prevalent. Genetic factors account for 40–60% of the risk factors for alcoholism. Similar rates of heritability for other types of drug addiction have been indicated, specifically in genes that encode the Alpha5 Nicotinic Acetylcholine Receptor.
Knestler hypothesized in 1964 that a gene or group of genes might
contribute to predisposition to addiction in several ways. For example,
altered levels of a normal protein due to environmental factors may
change the structure or functioning of specific brain neurons during
development. These altered brain neurons could affect the susceptibility
of an individual to an initial drug use experience. In support of this
hypothesis, animal studies have shown that environmental factors such as
stress can affect an animal's genetic expression.
In humans, twin studies into addiction have provided some of the
highest-quality evidence of this link, with results finding that if one
twin is affected by addiction, the other twin is likely to be as well,
and to the same substance.
Further evidence of a genetic component is research findings from
family studies which suggest that if one family member has a history of
addiction, the chances of a relative or close family developing those
same habits are much higher than one who has not been introduced to
addiction at a young age.
The data implicating specific genes in the development of drug
addiction is mixed for most genes. Many addiction studies that aim to
identify specific genes focus on common variants with an allele
frequency of greater than 5% in the general population. When associated
with disease, these only confer a small amount of additional risk with
an odds ratio
of 1.1–1.3 percent; this has led to the development the rare variant
hypothesis, which states that genes with low frequencies in the
population (<1%) confer much greater additional risk in the
development of the disease.
Genome-wide association studies (GWAS) are used to examine genetic associations with dependence, addiction, and drug use.
These studies rarely identify genes from proteins previously described
via animal knockout models and candidate gene analysis. Instead, large
percentages of genes involved in processes such as cell adhesion are
commonly identified. The important effects of endophenotypes
are typically not capable of being captured by these methods. Genes
identified in GWAS for drug addiction may be involved either in
adjusting brain behavior before drug experiences, subsequent to them, or
both.
Environmental factors
Environmental
risk factors for addiction are the experiences of an individual during
their lifetime that interact with the individual's genetic composition
to increase or decrease his or her vulnerability to addiction.
For example, after the nationwide outbreak of COVID-19, more people
quit (vs. started) smoking; and smokers, on average, reduced the
quantity of cigarettes they consumed.
More generally, a number of different environmental factors have been
implicated as risk factors for addiction, including various psychosocial stressors. The National Institute on Drug Abuse
(NIDA) and studies cite lack of parental supervision, the prevalence of
peer substance use, substance availability, and poverty as risk factors
for substance use among children and adolescents.
The brain disease model of addiction posits that an individual's
exposure to an addictive drug is the most significant environmental risk
factor for addiction.
Many researchers, including neuroscientists, indicate that the brain
disease model presents a misleading, incomplete, and potentially
detrimental explanation of addiction.
The psychoanalytic theory model defines addiction as a
form of defense against feelings of hopelessness and helplessness as
well as a symptom of failure to regulate powerful emotions related to
adverse childhood experiences (ACEs), various forms of maltreatment and
dysfunction experienced in childhood. In this case, the addictive
substance provides brief but total relief and positive feelings of
control. The Adverse Childhood Experiences Study by the Centers for Disease Control and Prevention has shown a strong dose–response relationship
between ACEs and numerous health, social, and behavioral problems
throughout a person's lifespan, including substance use disorder.
Children's neurological development can be permanently disrupted when
they are chronically exposed to stressful events such as physical,
emotional, or sexual abuse, physical or emotional neglect, witnessing
violence in the household, or a parent being incarcerated or having a
mental illness. As a result, the child's cognitive functioning or
ability to cope with negative or disruptive emotions may be impaired.
Over time, the child may adopt substance use as a coping mechanism or as
a result of reduced impulse control, particularly during adolescence. Vast amounts of children who experienced abuse have gone on to have some form of addiction in their adolescence or adult life.
This pathway towards addiction that is opened through stressful
experiences during childhood can be avoided by a change in environmental
factors throughout an individual's life and opportunities of
professional help.
If one has friends or peers who engage in drug use favorably, the
chances of them developing an addiction increases. Family conflict and
home management is a cause for one to become engaged in drug use.
According to Travis Hirschi's social control theory, adolescents with
stronger attachments to family, religious, academic, and other social
institutions are less likely to engage in delinquent and maladaptive
behavior such as drug use leading to addiction.
Age
Adolescence represents a period of increased vulnerability for developing an addiction.
In adolescence, the incentive-rewards systems in the brain mature well
before the cognitive control center. This consequentially grants the
incentive-rewards systems a disproportionate amount of power in the
behavioral decision-making process. Therefore, adolescents are
increasingly likely to act on their impulses and engage in risky,
potentially addicting behavior before considering the consequences.
Not only are adolescents more likely to initiate and maintain drug use,
but once addicted they are more resistant to treatment and more liable
to relapse.
Most individuals are exposed to and use addictive drugs for the first time during their teenage years. In the United States, there were just over 2.8 million new users of illicit drugs in 2013 (7,800 new users per day); among them, 54.1% were under 18 years of age. In 2011, there were approximately 20.6 million people in the United States over the age of 12 with an addiction. Over 90% of those with an addiction began drinking, smoking or using illicit drugs before the age of 18.
Comorbid disorders
Individuals with comorbid (i.e., co-occurring) mental health
disorders such as depression, anxiety, attention-deficit/hyperactivity
disorder (ADHD) or post-traumatic stress disorder are more likely to
develop substance use disorders. The NIDA cites early aggressive behavior as a risk factor for substance use. The National Bureau of Economic Research
found that there is a "definite connection between mental illness and
the use of addictive substances" and a majority of mental health
patients participate in the use of these substances: 38% alcohol, 44%
cocaine, and 40% cigarettes.
Epigenetic
Epigenetics is the study of stable phenotypic changes that do not involve alterations in the DNA sequence. Illicit drug use has been found to cause epigenetic changes in DNA methylation, as well as chromatin remodeling. The epigenetic state of chromatin may pose as a risk for the development of substance addictions.
It has been found that emotional stressors, as well as social
adversities may lead to an initial epigenetic response, which causes an
alteration to the reward-signalling pathways. This change may predispose one to experience a positive response to drug use.
Epigenetic
genes and their products (e.g., proteins) are the key components
through which environmental influences can affect the genes of an
individual: they serve as the mechanism responsible for transgenerational epigenetic inheritance, a phenomenon in which environmental influences on the genes of a parent can affect the associated traits and behavioral phenotypes of their offspring (e.g., behavioral responses to environmental stimuli). In addiction, epigenetic mechanisms play a central role in the pathophysiology of the disease; it has been noted that some of the alterations to the epigenome
which arise through chronic exposure to addictive stimuli during an
addiction can be transmitted across generations, in turn affecting the
behavior of one's children (e.g., the child's behavioral responses to
addictive drugs and natural rewards).
The general classes of epigenetic alterations that have been
implicated in transgenerational epigenetic inheritance include DNA
methylation, histone modifications, and downregulation or upregulation of microRNAs. With respect to addiction, more research is needed to determine the specific heritable
epigenetic alterations that arise from various forms of addiction in
humans and the corresponding behavioral phenotypes from these epigenetic
alterations that occur in human offspring. Based on preclinical evidence from animal research,
certain addiction-induced epigenetic alterations in rats can be
transmitted from parent to offspring and produce behavioral phenotypes
that decrease the offspring's risk of developing an addiction.
More generally, the heritable behavioral phenotypes that are derived
from addiction-induced epigenetic alterations and transmitted from
parent to offspring may serve to either increase or decrease the
offspring's risk of developing an addiction.
Mechanisms
Addiction is a disorder of the brain's reward system developing through transcriptional
and epigenetic mechanisms as a result of chronically high levels of
exposure to an addictive stimulus (e.g., eating food, the use of
cocaine, engagement in sexual activity, participation in high-thrill
cultural activities such as gambling, etc.) over extended time. DeltaFosB (ΔFosB), a gene transcription factor, is a critical component and common factor in the development of virtually all forms of behavioral and drug addictions.
Two decades of research into ΔFosB's role in addiction have
demonstrated that addiction arises, and the associated compulsive
behavior intensifies or attenuates, along with the overexpression of ΔFosB in the D1-typemedium spiny neurons of the nucleus accumbens. Due to the causal relationship between ΔFosB expression and addictions, it is used preclinically as an addiction biomarker. ΔFosB expression in these neurons directly and positively regulates drug self-administration and reward sensitization through positive reinforcement, while decreasing sensitivity to aversion.
Transcription factor glossary
gene expression – the process by which information from a gene is used in the synthesis of a functional gene product such as a protein
Chronic addictive drug use causes alterations in gene expression in the mesocorticolimbic projection. The most important transcription factors that produce these alterations are ΔFosB, cAMP response element binding protein (CREB), and nuclear factor kappa B (NF-κB).
ΔFosB is the most significant biomolecular mechanism in addiction
because the overexpression of ΔFosB in the D1-type medium spiny neurons
in the nucleus accumbens is necessary and sufficient
for many of the neural adaptations and behavioral effects (e.g.,
expression-dependent increases in drug self-administration and reward sensitization) seen in drug addiction. ΔFosB expression in nucleus accumbens D1-type medium spiny neurons directly and positively regulates drug self-administration and reward sensitization through positive reinforcement while decreasing sensitivity to aversion.[note 2][3][124]
ΔFosB has been implicated in mediating addictions to many different
drugs and drug classes, including alcohol, amphetamine and other substituted amphetamines, cannabinoids, cocaine, methylphenidate, nicotine, opiates, phenylcyclidine, and propofol, among others. ΔJunD, a transcription factor, and G9a, a histone methyltransferase, both oppose the function of ΔFosB and inhibit increases in its expression. Increases in nucleus accumbens ΔJunD expression (via viral vector-mediated
gene transfer) or G9a expression (via pharmacological means) reduces,
or with a large increase can even block, many of the neural and
behavioral alterations that result from chronic high-dose use of
addictive drugs (i.e., the alterations mediated by ΔFosB).
ΔFosB plays an important role in regulating behavioral responses to natural rewards, such as palatable food, sex, and exercise. Natural rewards, like drugs of abuse, induce gene expression
of ΔFosB in the nucleus accumbens, and chronic acquisition of these
rewards can result in a similar pathological addictive state through
ΔFosB overexpression.
Consequently, ΔFosB is the key transcription factor involved in
addictions to natural rewards (i.e., behavioral addictions) as well; in particular, ΔFosB in the nucleus accumbens is critical for the reinforcing effects of sexual reward.
Research on the interaction between natural and drug rewards suggests
that dopaminergic psychostimulants (e.g., amphetamine) and sexual
behavior act on similar biomolecular mechanisms to induce ΔFosB in the
nucleus accumbens and possess bidirectional cross-sensitization effects that are mediated through ΔFosB.
This phenomenon is notable since, in humans, a dopamine dysregulation
syndrome, characterized by drug-induced compulsive engagement in natural
rewards (specifically, sexual activity, shopping, and gambling), has
been observed in some individuals taking dopaminergic medications.
ΔFosB inhibitors (drugs or treatments that oppose its action) may
be an effective treatment for addiction and addictive disorders.
The release of dopamine in the nucleus accumbens plays a role in
the reinforcing qualities of many forms of stimuli, including naturally
reinforcing stimuli like palatable food and sex. Altered dopamine neurotransmission is frequently observed following the development of an addictive state. In humans and lab animals that have developed an addiction, alterations in dopamine or opioid neurotransmission in the nucleus accumbens and other parts of the striatum are evident. Use of certain drugs (e.g., cocaine) affect cholinergic neurons that innervate the reward system, in turn affecting dopamine signaling in this region.
A recent study in Addiction reports that GLP-1 agonist medications, such as semaglutide, which are commonly used for diabetes and weight management, may also reduce the risk of overdose and alcohol intoxication in people with substance use disorders.
The study analyzed nearly nine years of health records from 1.3 million
individuals across 136 U.S. hospitals, including 500,000 with opioid
use disorder and over 800,000 with alcohol use disorder.
Researchers found that those who used Ozempic or similar medications
had a 40% lower risk of opioid overdose and a 50% lower risk of alcohol
intoxication compared to those not using these drugs.
Top: this depicts the initial effects of high dose exposure to an addictive drug on gene expression in the nucleus accumbens for various Fos family proteins (i.e., c-Fos, FosB, ΔFosB, Fra1, and Fra2). Bottom:
this illustrates the progressive increase in ΔFosB expression in the
nucleus accumbens following repeated twice daily drug binges, where
these phosphorylated (35–37 kilodalton) ΔFosB isoforms persist in the D1-typemedium spiny neurons of the nucleus accumbens for up to 2 months.
Understanding the pathways in which drugs act and how drugs can alter
those pathways is key when examining the biological basis of drug
addiction. The reward pathway, known as the mesolimbic pathway, or its extension, the mesocorticolimbic pathway, is characterized by the interaction of several areas of the brain.
The projections from the ventral tegmental area (VTA) are a network of dopaminergicneurons with co-localized postsynaptic glutamate receptors (AMPAR and NMDAR). These cells respond when stimuli indicative of a reward are present. The VTA supports learning and sensitization development and releases dopamine (DA) into the forebrain. These neurons project and release DA into the nucleus accumbens, through the mesolimbic pathway. Virtually all drugs causing drug addiction increase the DA release in the mesolimbic pathway.
The nucleus accumbens (NAcc) is one output of the VTA projections. The nucleus accumbens itself consists mainly of GABAergicmedium spiny neurons (MSNs).
The NAcc is associated with acquiring and eliciting conditioned
behaviors, and is involved in the increased sensitivity to drugs as
addiction progresses. Overexpression of ΔFosB in the nucleus accumbens is a necessary common factor in essentially all known forms of addiction; ΔFosB is a strong positive modulator of positively reinforced behaviors.
The prefrontal cortex, including the anterior cingulate and orbitofrontal cortices,
is another VTA output in the mesocorticolimbic pathway; it is important
for the integration of information which helps determine whether a
behavior will be elicited.
It is critical for forming associations between the rewarding
experience of drug use and cues in the environment. Importantly, these
cues are strong mediators of drug-seeking behavior and can trigger
relapse even after months or years of abstinence.
Other brain structures that are involved in addiction include:
The basolateral amygdala projects into the NAcc and is thought to be important for motivation.
The hippocampus
is involved in drug addiction, because of its role in learning and
memory. Much of this evidence stems from investigations showing that
manipulating cells in the hippocampus alters DA levels in NAcc and
firing rates of VTA dopaminergic cells.
Role of dopamine and glutamate
Dopamine
is the primary neurotransmitter of the reward system in the brain. It
plays a role in regulating movement, emotion, cognition, motivation, and
feelings of pleasure.
Natural rewards, like eating, as well as recreational drug use cause a
release of dopamine, and are associated with the reinforcing nature of
these stimuli. Nearly all addictive drugs, directly or indirectly, act on the brain's reward system by heightening dopaminergic activity.
Excessive intake of many types of addictive drugs results in
repeated release of high amounts of dopamine, which in turn affects the
reward pathway directly through heightened dopamine receptor activation.
Prolonged and abnormally high levels of dopamine in the synaptic cleft can induce receptor downregulation in the neural pathway. Downregulation of mesolimbic dopamine receptors can result in a decrease in the sensitivity to natural reinforcers.
Drug seeking behavior is induced by glutamatergic projections
from the prefrontal cortex to the nucleus accumbens. This idea is
supported with data from experiments showing that drug seeking behavior
can be prevented following the inhibition of AMPA glutamate receptors and glutamate release in the nucleus accumbens.
Reward sensitization
Neural and behavioral effects of validated ΔFosB transcriptional targets in the striatum
• GluR1 synaptic protein phosphorylation • Expansion of NAcc dendritic processes
Decreased drug reward (net effect)
Reward sensitization is a process that causes an increase in the amount of reward (specifically, incentive salience)
that is assigned by the brain to a rewarding stimulus (e.g., a drug).
In simple terms, when reward sensitization to a specific stimulus (e.g.,
a drug) occurs, an individual's "wanting" or desire for the stimulus
itself and its associated cues increases. Reward sensitization normally occurs following chronically high levels of exposure to the stimulus.
ΔFosB expression in D1-type medium spiny neurons in the nucleus
accumbens has been shown to directly and positively regulate reward
sensitization involving drugs and natural rewards.
"Cue-induced wanting" or "cue-triggered wanting", a form of
craving that occurs in addiction, is responsible for most of the
compulsive behavior that people with addictions exhibit. During the development of an addiction, the repeated association of otherwise neutral and even non-rewarding stimuli with drug consumption triggers an associative learning process that causes these previously neutral stimuli to act as conditioned positive reinforcers of addictive drug use (i.e., these stimuli start to function as drug cues).
As conditioned positive reinforcers of drug use, these previously
neutral stimuli are assigned incentive salience (which manifests as a
craving) – sometimes at pathologically high levels due to reward
sensitization – which can transfer to the primary reinforcer (e.g., the use of an addictive drug) with which it was originally paired.
Research on the interaction between natural and drug rewards
suggests that dopaminergic psychostimulants (e.g., amphetamine) and
sexual behavior act on similar biomolecular mechanisms to induce ΔFosB
in the nucleus accumbens and possess a bidirectional reward cross-sensitization effect that is mediated through ΔFosB. In contrast to ΔFosB's reward-sensitizing effect, CREB
transcriptional activity decreases user's sensitivity to the rewarding
effects of the substance. CREB transcription in the nucleus accumbens is
implicated in psychological dependence and symptoms involving a lack of pleasure or motivation during drug withdrawal.
Altered epigenetic regulation of gene expression within the brain's
reward system plays a significant and complex role in the development of
drug addiction. Addictive drugs are associated with three types of epigenetic modifications within neurons. These are (1) histone modifications, (2) epigenetic methylation of DNA at CpG sites
at (or adjacent to) particular genes, and (3) epigenetic downregulation
or upregulation of microRNAs which have particular target genes.
As an example, while hundreds of genes in the cells of the nucleus
accumbens (NAc) exhibit histone modifications following drug exposure –
particularly, altered acetylation and methylation states of histoneresidues – most other genes in the NAc cells do not show such changes.
The fifth edition of the DSM uses the term substance use disorder to refer to a spectrum of drug use-related disorders. The DSM-5 eliminates the terms abuse and dependence from diagnostic categories, instead using the specifiers of mild, moderate and severe
to indicate the extent of disordered use. These specifiers are
determined by the number of diagnostic criteria present in a given case.
In the DSM-5, the term drug addiction is synonymous with severe substance use disorder.
The DSM-5 introduced a new diagnostic category for behavioral
addictions. Problem gambling is the only condition included in this
category in the fifth edition. Internet gaming disorder is listed as a "condition requiring further study" in the DSM-5.
Past editions have used physical dependence
and the associated withdrawal syndrome to identify an addictive state.
Physical dependence occurs when the body has adjusted by incorporating
the substance into its "normal" functioning – i.e., attains homeostasis – and therefore physical withdrawal symptoms occur on cessation of use.
Tolerance is the process by which the body continually adapts to the
substance and requires increasingly larger amounts to achieve the
original effects. Withdrawal refers to physical and psychological
symptoms experienced when reducing or discontinuing a substance that the
body has become dependent on. Symptoms of withdrawal generally include
but are not limited to body aches, anxiety, irritability, intense cravings for the substance, dysphoria, nausea, hallucinations, headaches, cold sweats, tremors, and seizures. During acute physical opioid withdrawal, symptoms of restless legs syndrome are common and may be profound. This phenomenon originated the idiom "kicking the habit".
Medical researchers who actively study addiction have criticized
the DSM classification of addiction for being flawed and involving
arbitrary diagnostic criteria.
ICD-11
The eleventh revision of the International Classification of Diseases, commonly referred to as ICD-11,
conceptualizes diagnosis somewhat differently. ICD-11 first
distinguishes between problems with psychoactive substance use
("Disorders due to substance use") and behavioral addictions ("Disorders
due to addictive behaviours").
With regard to psychoactive substances, ICD-11 explains that the
included substances initially produce "pleasant or appealing
psychoactive effects that are rewarding and reinforcing with repeated
use, [but] with continued use, many of the included substances have the
capacity to produce dependence. They have the potential to cause
numerous forms of harm, both to mental and physical health."
Instead of the DSM-5 approach of one diagnosis ("Substance Use
Disorder") covering all types of problematic substance use, ICD-11
offers three diagnostic possibilities: 1) Episode of Harmful
Psychoactive Substance Use, 2) Harmful Pattern of Psychoactive Substance
Use, and 3) Substance Dependence.
Abuse
or addiction liability is the tendency to use drugs in a non-medical
situation. This is typically for euphoria, mood changing, or sedation.
Abuse liability is used when the person using the drugs wants something
that they otherwise can not obtain. The only way to obtain this is
through the use of drugs. When looking at abuse liability there are a
number of determining factors in whether the drug is abused. These
factors are: the chemical makeup of the drug, the effects on the brain,
and the age, vulnerability, and the health (mental and physical) of the
population being studied.
There are a few drugs with a specific chemical makeup that leads to a
high abuse liability. These are: cocaine, heroin, inhalants, marijuana,
MDMA (ecstasy), methamphetamine, PCP, synthetic cannabinoids, synthetic
cathinones (bath salts), nicotine (e.g. tobacco), and alcohol.
Potential vaccines for addiction to substances
Vaccines for addiction have been investigated as a possibility since the early 2000s. The general theory of a vaccine intended to "immunize" against drug addiction or other substance abuse is that it would condition the immune system
to attack and consume or otherwise disable the molecules of such
substances that cause a reaction in the brain, thus preventing the
addict from being able to realize the effect of the drug. Addictions
that have been floated as targets for such treatment include nicotine, opioids, and fentanyl.
Vaccines have been identified as potentially being more effective than
other anti-addiction treatments, due to "the long duration of action,
the certainty of administration and a potential reduction of toxicity to important organs".
Specific addiction vaccines in development include:
TA-CD, an active vaccine developed by the Xenova Group which is used to negate the effects of cocaine. It is created by combining norcocaine with inactivated cholera toxin. It works in much the same way as a regular vaccine. A large protein molecule attaches to cocaine, which stimulates response from antibodies, which destroy the molecule. This also prevents the cocaine from crossing the blood–brain barrier, negating the euphoric high and rewarding effect of cocaine caused from stimulation of dopamine release in the mesolimbic reward pathway. The vaccine does not affect the user's "desire" for cocaine—only the physical effects of the drug.
TA-NIC, used to create human antibodies to destroy nicotine in the human body so that it is no longer effective.
As of September 2023, it was further reported that a vaccine "has been tested against heroin and fentanyl and is on its way to being tested against OxyContin".
To be effective, treatment for addiction that is pharmacological or
biologically based need to be accompanied by other interventions such as
cognitive behavioral therapy (CBT) and dialectical behavioral therapy (DBT);individual and group psychotherapy, behavior modification strategies, twelve-step programs, and residential treatment facilities. The transtheoretical model
(TTM) can be used to determine when treatment can begin and which
method will be most effective. If treatment begins too early, it can
cause a person to become defensive and resistant to change.
Due to cultural variations, the proportion of individuals who develop
a drug or behavioral addiction within a specified time period (i.e.,
the prevalence) varies over time, by country, and across national population demographics (e.g., by age group, socioeconomic status, etc.). Where addiction is viewed as unacceptable, there will be fewer people addicted.
Asia
The
prevalence of alcohol dependence is not as high as is seen in other
regions. In Asia, not only socioeconomic factors but biological factors
influence drinking behavior.
Internet addiction disorder is highest in the Philippines,
according to both the IAT (Internet Addiction Test) – 5% and the CIAS-R
(Revised Chen Internet Addiction Scale) – 21%.
The prevalence of substance use disorder among Australians was reported at 5.1% in 2009. In 2019 the Australian Institute of Health and Welfare conducted a national drug survey that quantified drug use for various types of drugs and demographics.
The survey found that in 2019, 11% of people over 14 years old smoke
daily; that 9.9% of those who drink alcohol, which equates to 7.5% of
the total population age 14 or older, may qualify as alcohol dependent;
that 17.5% of the 2.4 million people who used cannabis in the last year
may have hazardous use or a dependence problem; and that 63.5% of about
300000 recent users of meth and amphetamines were at risk for developing
problem use.
In 2015, the estimated prevalence among the adult population was
18.4% for heavy episodic alcohol use (in the past 30 days); 15.2% for
daily tobacco smoking; and 3.8% for cannabis use, 0.77% for amphetamine
use, 0.37% for opioid use, and 0.35% for cocaine use in 2017. The
mortality rates for alcohol and illicit drugs were highest in Eastern
Europe.
Data shows a downward trend of alcohol use among children 15 years old
in most European countries between 2002 and 2014. First-time alcohol use
before the age of 13 was recorded for 28% of European children in 2014.
Based on representative samples of the US youth population in 2011, the lifetime prevalence of addictions to alcohol and illicit drugs has been estimated to be approximately 8% and 2–3% respectively. Based on representative samples of the US adult population in 2011, the 12-month prevalence of alcohol and illicit drug addictions were estimated at 12% and 2–3% respectively. The lifetime prevalence of prescription drug addictions is around 4.7%.
As of 2021, 43.7 million people aged 12 or older surveyed by the
National Survey on Drug Use and Health in the United States needed
treatment for an addiction to alcohol, nicotine, or other drugs. The
groups with the highest number of people were 18–25 years (25.1%) and
"American Indian or Alaska Native" (28.7%). Only about 10%, or a little over 2 million, receive any form of treatments, and those that do generally do not receive evidence-based care. One-third of inpatient hospital costs and 20% of all deaths in the US every year are the result of untreated addictions and risky substance use. In spite of the massive overall economic cost to society, which is greater than the cost of diabetes and all forms of cancer combined, most doctors in the US lack the training to effectively address a drug addiction.
Estimates of lifetime prevalence rates in the US are 1–2% for
compulsive gambling, 5% for sexual addiction, 2.8% for food addiction,
and 5–6% for compulsive shopping.
The time-invariant prevalence rate for sexual addiction and related
compulsive sexual behavior (e.g., compulsive masturbation with or
without pornography, compulsive cybersex, etc.) within the US ranges
from 3–6% of the population.
According to a 2017 poll conducted by the Pew Research Center,
almost half of US adults know a family member or close friend who has
struggled with a drug addiction at some point in their life.
In 2019, opioid addiction was acknowledged as a national crisis in the United States. An article in The Washington Post
stated that "America's largest drug companies flooded the country with
pain pills from 2006 through 2012, even when it became apparent that
they were fueling addiction and overdoses."
The National Epidemiologic Survey on Alcohol and Related Conditions found that from 2012 to 2013 the prevalence of Cannabis use disorder in U.S. adults was 2.9%.
Canada
A Statistics Canada
Survey in 2012 found the lifetime prevalence and 12-month prevalence of
substance use disorders were 21.6%, and 4.4% in those 15 and older. Alcohol abuse or dependence reported a lifetime prevalence of 18.1% and a 12-month prevalence of 3.2%. Cannabis abuse or dependence reported a lifetime prevalence of 6.8% and a 12-month prevalence of 3.2%. Other drug abuse or dependence has a lifetime prevalence of 4.0% and a 12-month prevalence of 0.7%. Substance use disorder is a term used interchangeably with a drug addiction.
In Ontario, Canada
between 2009 and 2017, outpatient visits for mental health and
addiction increased from 52.6 to 57.2 per 100 people, emergency
department visits increased from 13.5 to 19.7 per 1000 people and the
number of hospitalizations increased from 4.5 to 5.5 per 1000 people. Prevalence of care needed increased the most among the 14–17 age group overall.
South America
The realities of opioid use and opioid use disorder in Latin America may be deceptive if observations are limited to epidemiological findings. In the United Nations Office on Drugs and Crime report,
although South America produced 3% of the world's morphine and heroin
and 0.01% of its opium, prevalence of use is uneven. According to the
Inter-American Commission on Drug Abuse Control, consumption of heroin
is low in most Latin American countries, although Colombia is the area's
largest opium producer. Mexico, because of its border with the United
States, has the highest incidence of use.
The etymology of the term addiction throughout history has been misunderstood and has taken on various meanings associated with the word. An example is the usage of the word in the religious landscape of early modern Europe.
"Addiction" at the time meant "to attach" to something, giving it both
positive and negative connotations. The object of this attachment could
be characterized as "good or bad". The meaning of addiction during the early modern period was mostly associated with positivity and goodness; during this early modern and highly religious era of Christian revivalism and Pietistic tendencies, it was seen as a way of "devoting oneself to another".
Modern research on addiction has led to a better understanding of the disease with research on the topic dating back to 1875, specifically on morphine addiction.
This furthered the understanding of addiction being a medical
condition. It was not until the 19th century that addiction was seen and
acknowledged in the Western world as a disease, being both a physical
condition and mental illness. Today, addiction is understood both as a biopsychosocial and neurological disorder that negatively impacts those who are affected by it, most commonly associated with the use of drugs and excessive use of alcohol.
The understanding of addiction has changed throughout history, which
has impacted and continues to impact the ways it is medically treated
and diagnosed.
The suffixes "-holic" and "-holism"
In contemporary modern English "-holic" is a suffix
that can be added to a subject to denote an addiction to it. It was
extracted from the word alcoholism (one of the first addictions to be
widely identified both medically and socially) (correctly the root "alcohol" plus the suffix "-ism") by misdividing or rebracketing it into "alco" and "-holism". There are correct medico-legal terms for such addictions: dipsomania is the medico-legal term for alcoholism; other examples are in this table:
The
arts can be used in a variety of ways to address issues related to
addiction. Art can be used as a form of therapy in the treatment of
substance use disorders. Creative activities like painting, sculpting,
music, and writing can help people express their feelings and
experiences in safe and healthy ways. The arts can be used as an
assessment tool to identify underlying issues that may be contributing
to a person's substance use disorder. Through art, individuals can gain
insights into their own motivations and behaviors that can be helpful in
determining a course of treatment. Finally, the arts can be used to
advocate for those suffering from a substance use disorder by raising
awareness of the issue and promoting understanding and compassion.
Through art, individuals can share their stories, increase awareness,
and offer support and hope to those struggling with substance use
disorders.
As therapy
Addiction
treatment is complex and not always effective due to engagement and
service availability concerns, so researchers prioritize efforts to
improve treatment retention and decrease relapse rates. Characteristics of substance abuse may include feelings of isolation, a lack of confidence, communication difficulties, and a perceived lack of control.
In a similar vein, people suffering from substance use disorders tend
to be highly sensitive, creative, and as such, are likely able to
express themselves meaningfully in creative arts such as dancing,
painting, writing, music, and acting. Further evidenced by Waller and Mahony (2002) and Kaufman (1981),
the creative arts therapies can be a suitable treatment option for this
population especially when verbal communication is ineffective.
Primary advantages of art therapy in the treatment of addiction have been identified as:
Assess and characterize a client's substance use issues
Bypassing a client's resistances, defenses, and denial
Containing shame or anger
Facilitating the expression of suppressed and/or complicated emotions
Highlighting a client's strengths
Providing an alternative to verbal communication (via use of symbols) and conventional forms of therapy
Providing clients with a sense of control
Tackling feelings of isolation
Art therapy is an effective method of dealing with substance abuse in
comprehensive treatment models. When included in psychoeducational
programs, art therapy in a group setting can help clients internalize
taught concepts in a more personalized manner.
During the course of treatment, by examining and comparing artwork
created at different times, art therapists can be helpful in identifying
and diagnosing issues, as well as charting the extent or direction of
improvement as a person detoxifies.
Where increasing adherence to treatment regimes and maintaining
abstinence is the target; art therapists can aid by customizing
treatment directives (encourage the client to create collages that
compare pros and cons, pictures that compare past and present and
future, and drawings that depict what happened when a client went off
medication).
Art therapy can function as a complementary therapy used in
conjunction with more conventional therapies and can can integrate with
harm reduction protocols to minimize the negative effects of drug use.
An evaluation of art therapy incorporation within a pre-existing
Addiction Treatment Programme based on the 12 step Minnesota Model
endorsed by the Alcoholics Anonymous found that 66% of participants
expressed the usefulness of art therapy as a part of treatment.
Within the weekly art therapy session, clients were able to reflect and
process the intense emotions and cognitions evoked by the programme. In
turn, the art therapy component of the programme fostered stronger
self-awareness, exploration, and externalization of repressed and
unconscious emotions of clients, promoting the development of a more
integrated 'authentic self'.
Despite the large number of randomized control trials, clinical
control trials, and anecdotal evidence supporting the effectiveness of
art therapies for use in addiction treatment, a systematic review
conducted in 2018 could not find enough evidence on visual art, drama,
dance and movement therapy, or 'arts in health' methodologies to confirm
their effectiveness as interventions for reducing substance misuse.
Music therapy was identified to have potentially strong beneficial
effects in aiding contemplation and preparing those diagnosed with
substance use for treatment.
As an assessment tool
The
Formal Elements Art Therapy Scale (FEATS) is an assessment tool used to
evaluate drawings created by people suffering from substance use
disorders by comparing them to drawings of a control group (consisting
of individuals without SUDs).
FEATS consists of twelve elements, three of which were found to be
particularly effective at distinguishing the drawings of those with SUDs
from those without: Person, Realism, and Developmental. The Person
element assesses the degree to which a human features are depicted
realistically, the Realism element assesses the overall complexity of
the artwork, and the Developmental element assesses "developmental age"
of the artwork in relation to standardized drawings from children and
adolescents.
By using the FEATS assessment tool, clinicians can gain valuable
insight into the drawings of individuals with SUDs, and can compare them
to those of the control group. Formal assessments such as FEATS provide
healthcare providers with a means to quantify, standardize, and
communicate abstract and visceral characteristics of SUDs to provide
more accurate diagnoses and informed treatment decisions.
Other artistic assessment methods include the Bird's Nest Drawing: a useful tool for visualizing a client's attachment security.
This assessment method looks at the amount of color used in the
drawing, with a lack of color indicating an 'insecure attachment', a
factor that the client's therapist or recovery framework must take into
account.
Art therapists working with children of parents suffering from
alcoholism can use the Kinetic Family Drawings assessment tool to shed
light on family dynamics and help children express and understand their
family experiences.
The KFD can be used in family sessions to allow children to share their
experiences and needs with parents who may be in recovery from alcohol
use disorder. Depiction of isolation of self and isolation of other
family members may be an indicator of parental alcoholism.
Advocacy
Stigma
can lead to feelings of shame that can prevent people with substance
use disorders from seeking help and interfere with provision of harm
reduction services. It can influence healthcare policy, making it difficult for these individuals to access treatment.
Artists attempt to change the societal perception of addiction
from a punishable moral offense to instead a chronic illness
necessitating treatment. This form of advocacy can help to relocate the
fight of addiction from a judicial perspective to the public health
system.
Artists who have personally lived with addiction and/or undergone
recovery may use art to depict their experiences in a manner that
uncovers the "human face of addiction". By bringing experiences of
addiction and recovery to a personal level and breaking down the "us and
them", the viewer may be more inclined to show compassion, forego
stereotypes and stigma of addiction, and label addiction as a social
rather than individual problem.
According to Santora the main purposes in using art as a form of advocacy in the education and prevention of substance use disorders include:
Addiction art exhibitions can come from a variety of sources,
but the underlying message of these works is the same: to communicate
through emotions without relying on intellectually demanding/gatekept
facts and figures. These exhibitions can either stand alone, reinforce,
or challenge facts.
A powerful educational tool for increasing awareness and
understanding of addiction as a medical illness. Exhibitions featuring
personal stories and images can help to create lasting impressions on
diverse audiences (including addiction scientists/researchers,
family/friends of those affected by addiction etc.), highlighting the
humanity of the problem and in turn encouraging compassion and
understanding.
A way to destigmatize substance use disorders and shift public
perception from viewing them as a moral failing to understanding them as
a chronic medical condition which requires treatment.
Provide those who are struggling with addiction assurance and
encouragement of healing, and let them know that they are not alone in
their struggle.
The use of visual arts can help bring attention to the lack of
adequate substance use treatment, prevention, and education programs and
services in a healthcare system. Messages can encourage policymakers to
allocate more resources to addiction treatment and prevention from
federal, state, and local levels.
The Temple University College of Public Health department conducted a
project to promote awareness around opioid use and reduce associated
stigma by asking students to create art pieces that were displayed on a
website they created and promoted via social media.
Quantitative and qualitative data was recorded to measure engagement,
and the student artists were interviewed, which revealed a change in
perspective and understanding, as well as greater appreciation of
diverse experiences. Ultimately, the project found that art was an
effective medium for empowering both the artist creating the work and
the person interacting with it.
Another author critically examined works by contemporary Canadian
artists that deal with addiction via the metaphor of a cultural
landscape to "unmap" and "remap" ideologies related to Indigenous
communities and addiction to demonstrate how colonial violence in Canada
has drastically impacted the relationship between Indigenous peoples,
their land, and substance abuse.
A project known as "Voice" was a collection of art, poetry and
narratives created by women living with a history of addiction to
explore women's understanding of harm reduction, challenge the effects
of stigma and give voice to those who have historically been silenced or
devalued.
In the project, nurses with knowledge of mainstream systems, aesthetic
knowing, feminism and substance use organized weekly gatherings, wherein
women with histories of substance use and addiction worked alongside a
nurse to create artistic expressions. Creations were presented at
several venues, including an International Conference on Drug Related
Harm, a Nursing Conference and a local gallery to positive community
response.
Narrative Approach and Addiction
The
narrative medicine to addiction focuses on recognizing, absorbing, and
interpreting the stories of those suffering from addiction, allowing for
better understanding of their experiences
with narrative analysis being used to study the discourse of those with
addiction. This knowledge can be used to develop better care plans with
the potential to increase patient compliance and make treatment more
effective.
A narrative study demonstrated and studied cognitive and
emotional tendencies among substance abusers during treatment periods to
learn more about motivation and ambivalence inherent in recovery over
the course of a residential treatment program.
Seven narrative types emerged from the overall analysis: optimistic,
overly optimistic, pessimistic, overly pessimistic, "tough life,"
troubled/confused, and balanced. Narratives tended to express a basic
level of emotionality in early stages of treatment ("optimistic",
"pessimistic" narrative). Over time, as clients progressed through the
program, their stories became more complex and detailed, including their
drug abuse and recovery efforts, more skeptical positions towards
treatment began to emerge. Clients began to distinguish between the
positive and negative aspects of treatment, creating more "balanced"
narratives in the process.
Due to higher medication consumption, social isolation, financial
worries, and other factors, older adults are particularly vulnerable to
substance use problems.
Incidence of addiction among this population is inaccurately reported.
Narrative therapy can provide an avenue to unearth stories of addiction
in an empowering manner, and thus serves as a viable therapeutic tool in
applied gerontology.
When treating substance abuse in older adults, it is essential to
ensure that the client is respected and comfortable disclosing
information. This should be done at the outset of treatment when the
therapist and older adult are developing the therapeutic relationship.
The social breakdown model is an important tool that can consider the
compounded effects of ageism, physical changes, social changes, and
substance abuse. The narrative approach integrates the social breakdown
model with substance abuse challenges and can be an effective way to
address addiction in this population.
A study conducted in 2009 in the Republic of Moldova looked into
the social dynamics of initiating injection drug usage by examining 42
audio-recorded, semi-structured interviews with present and former
injectors.
A thematic analysis suggested that self-injection was viewed as a
symbolic transition of identity, enabled by interpersonal interactions
and collective influences. Personal narratives of self-transition were
connected to larger narratives of social transitions. The personal
narratives of self-initiation and transition are contextualized and
understood in terms of political (social) narratives within the core
concept of the 'transitional society'.
Another study examined the narratives of 'initiators': people who help
people who inject drugs (PWID) with their first injection.
Through their accounts, respondents described initiation events as
meaningful transitions to a life characterized by predictable downfalls
of homelessness, infections, and social stigma.
Initiators used examples from their own personal experience to explain
the process of initiation and assistance, attributing personal agency
and predicting specific injection-related harms for initiates. They
distinguished between two forms of harm: potentially avoidable proximal
harm caused by risky injection practices (e.g. overdose, HIV) and
perceived inevitable distal harm caused by long-term injection (e.g.
socioeconomic decline).
In this way, these narratives reflect a balance of individual agency,
harm reduction intentions, and accepted notions of 'life after
initiation' interact with the narrative experiences and intentions of
PWIDs.
Philosophy
From
a philosophy perspective, the behavior of many with addiction that is
not explained by executive dysfunction or biological reasons can be
explained by folk psychology – specifically the belief–desire model.
According to this model, a person acquires and uses a substance or does
an addictive activity in belief that it will help them achieve a goal.
While regarded biomedically as a neuropsychological disorder, addiction is multi-layered, with biological, psychological, social, cultural, and spiritual (biopsychosocial–cultural–spiritual) elements. A biopsychosocial–cultural–spiritual approach fosters the crossing of disciplinary boundaries, and promotes holistic considerations of addiction.
A biopsychosocial–cultural–spiritual approach considers, for example,
how physical environments influence experiences, habits, and patterns of
addiction.
Ethnographic
engagements and developments in fields of knowledge have contributed to
biopsychosocial–cultural–spiritual understandings of addiction,
including the work of Philippe Bourgois, whose fieldwork with street-level drug dealers in East Harlem highlights correlations between drug use and structural oppression in the United States. Prior models that have informed the prevailing biopsychosocial–cultural–spiritual consideration of addiction include:
Cultural model
The cultural model, an anthropological understanding of the emergence of drug use and abuse, was developed by Dwight Heath. Heath undertook ethnographic research and fieldwork with the Camba people of Bolivia from June 1956 to August 1957. Heath observed that adult members of society drank 'large quantities of rum and became intoxicated for several contiguous days at least twice a month'. This frequent, heavy drinking from which intoxication followed was typically undertaken socially, during festivals.
Having returned in 1989, Heath observed that while much had changed,
'drinking parties' remained, as per his initial observations, and 'there
appear to be no harmful consequences to anyone'. Heath's observations and interactions reflected that this form of social behavior, the habitual heavy consumption of alcohol, was encouraged and valued, enforcing social bonds in the Camba community.
Despite frequent intoxication, "even to the point of unconsciousness",
the Camba held no concept of alcoholism (a form of addiction), and no
visible social problems associated with drunkenness, or addiction, were
apparent.
As noted by Merrill Singer, Heath's findings, when considered alongside subsequent cross-cultural experiences, challenged the perception that intoxication is socially 'inherently disruptive'. Following this fieldwork,
Heath proposed the 'cultural model', suggesting that 'problems'
associated with heavy drinking, such as alcoholism – a recognised form
addiction – were cultural: that is, that alcoholism is determined by
cultural beliefs, and therefore varies among cultures. Heath's findings
challenged the notion that 'continued use [of alcohol] is inexorably
addictive and damaging to the consumer's health'.
The cultural model did face criticism by SociologistRobin Room and others, who felt anthropologists could "downgrade the severity of the problem".
Merrill Singer found it notable that the ethnographers working within
the prominence of the cultural model were part of the 'wet generation':
while not blind to the 'disruptive, dysfunctional and debilitating
effects of alcohol consumption', they were products 'socialized to view
alcohol consumption as normal'.
Subcultural model
Historically, addiction has been viewed from the etic perspective, defining users through the pathology of their condition.
As reports of drug use rapidly increased, the cultural model found
application in anthropological research exploring western drug subculture practices.
The approach evolved from the ethnographic exploration into the lived experiences and subjectivities of 1960s and 1970s drug subcultures.
The seminal publication "Taking care of business", by Edward Preble and
John J. Casey, documented the daily lives of New York street-based
intravenous heroin users in rich detail, providing unique insight into
the dynamic social worlds and activities that surrounded their drug use. These findings challenge popular narratives of immorality and deviance, conceptualizing substance abuse as a social phenomenon.
The prevailing culture can have a greater influence on drug taking
behaviors than the physical and psychological effects of the drug
itself. To marginalized individuals, drug subcultures can provide social connection, symbolic meaning, and socially constructed purpose that they may feel is unattainable through conventional means.
The subcultural model demonstrates the complexities of addiction,
highlighting the need for an integrated approach. It contends that a biosocial approach is required to achieve a holistic understanding of addiction.
Critical medical anthropology model
Emerging
in the early 1980s, the critical medical anthropology model was
introduced, and as Merrill Singer offers 'was applied quickly to the
analysis of drug use'. Where the cultural model of the 1950s looked at the social body, the critical medical anthropology model revealed the body politic, considering drug use and addiction within the context of macro level structures including larger political systems, economic inequalities, and the institutional power held over social processes.
Highly relevant to addiction, the three issues emphasized in the model are:
These three key points highlight how drugs may come to be used to self-medicate the psychological trauma of socio-political disparity and injustice, intertwining with licit and illicit drug market politics.
Social suffering, "the misery among those on the weaker end of power
relations in terms of physical health, mental health and lived
experience", is used by anthropologists to analyze how individuals may
have personal problems caused by political and economic power.
From the perspective of critical medical anthropology heavy drug use
and addiction is a consequence of such larger scale unequal
distributions of power.
The three models developed here – the cultural model, the
subcultural model, and the Critical Medical Anthropology Model – display
how addiction is not an experience to be considered only biomedically.
Through consideration of addiction alongside the biological,
psychological, social, cultural and spiritual
(biopsychosocial–spiritual) elements which influence its experience, a
holistic and comprehensive understanding can be built.
Albert Bandura's 1977 social learning theory posits that individuals
acquire addictive behaviors by observing and imitating models in their
social environment.
The likelihood of engaging in and sustaining similar addictive
behaviors is influenced by the reinforcement and punishment observed in
others. The principle of reciprocal determinism suggests that the
functional relationships between personal, environmental, and behavioral
factors act as determinants of addictive behavior. Thus, effective treatment targets each dynamic facet of the biopsychosocial disorder.
The transtheoretical model of change suggests that overcoming an
addiction is a stepwise process that occurs through several stages.
Precontemplation: This initial stage precedes individuals
considering a change in their behavior. They might be oblivious to or in
denial of their addiction, failing to recognize the need for change.
Contemplation is the stage in which individuals become
aware of the problems caused by their addiction and are considering
change. Although they may not fully commit, they weigh the costs and
benefits of making a shift.
Preparation: Individuals in this stage are getting ready
to change. They might have taken preliminary steps, like gathering
information or making small commitments, in preparation for behavioral
change.
Action involves actively modifying behavior by making
specific, observable changes to address the addictive behavior. The
action stage requires significant effort and commitment.
Maintenance: After successfully implementing a change,
individuals enter the maintenance stage, where they work to sustain the
new behavior and prevent relapse. This stage is characterized by ongoing
effort and consolidation of gains.
Termination/relapse prevention: Recognizing that relapse
is a common part of the change process, this stage focuses on
identifying and addressing factors that may lead to a return to old
behaviors. Relapse is viewed as an opportunity for learning and strategy
adjustment, with the ultimate goal of eliminating or terminating the
targeted behavior.
The transtheoretical model can be helpful in guiding development
of tailored behavioral interventions that can promote lasting change.
Progression through these stages may not always follow a linear path, as
individuals may move back and forth between stages. Resistance to
change is recognized as an expected part of the process.
Addiction causes an "astoundingly high financial and human toll" on individuals and society as a whole.
In the United States, the total economic cost to society is greater
than that of all types of diabetes and all cancers combined.
These costs arise from the direct adverse effects of drugs and
associated healthcare costs (e.g., emergency medical services and
outpatient and inpatient care), long-term complications (e.g., lung
cancer from smoking tobacco products, liver cirrhosis and dementia from chronic alcohol consumption, and meth mouth
from methamphetamine use), the loss of productivity and associated
welfare costs, fatal and non-fatal accidents (e.g., traffic collisions),
suicides, homicides, and incarceration, among others.
The US National Institute on Drug Abuse has found that overdose deaths
in the US have almost tripled among male and females from 2002 to 2017,
with 72,306 overdose deaths reported in 2017 in the US.
2020 marked the year with highest number of overdose deaths over a
12-month period, with 81,000 overdose deaths, exceeding the records set
in 2017.
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