| Phobia | |
|---|---|
 | |
| The fear of spiders is one of the most common phobias | |
| Specialty | Psychiatry, clinical psychology |
| Symptoms | Fear of an object or situation |
| Complications | Suicide |
| Usual onset | Rapid |
| Duration | More than six months |
| Types | Specific phobias, social phobia, agoraphobia |
| Causes | Unknown, some genetic effects |
| Treatment | Exposure therapy, counselling, medication |
| Medication | Antidepressants, benzodiazepines, beta-blockers |
| Frequency | Specific phobias: ~5% Social phobia: ~5% Agoraphobia: ~2% |
A phobia is a type of anxiety disorder defined by a persistent and excessive fear of an object or situation. The phobia typically results in a rapid onset of fear and is present for more than six months. The affected person goes to great lengths to avoid the situation or object, to a degree greater than the actual danger posed. If the feared object or situation cannot be avoided, the affected person experiences significant distress. With blood or injury phobia, fainting may occur. Agoraphobia is often associated with panic attacks. Usually a person has phobias to a number of objects or situations.
Phobias can be divided into specific phobias, social phobia, and agoraphobia. Types of specific phobias include those to certain animals, natural environment situations, blood or injury, and specific situations.[1] The most common are fear of spiders, fear of snakes, and fear of heights. Occasionally they are triggered by a negative experience with the object or situation. Social phobia is when the situation is feared as the person is worried about others judging them. Agoraphobia is when fear of a situation occurs because it is felt that escape would not be possible.
It is recommended that specific phobias be treated with exposure therapy where the person is introduced to the situation or object in question until the fear resolves. Medications are not useful in this type of phobia. Social phobia and agoraphobia are often treated with some combination of counselling and medication. Medications used include antidepressants, benzodiazepines, or beta-blockers.
Specific phobias affect about 6–8% of people in the Western world and 2–4% of people in Asia, Africa, and Latin America in a given year. Social phobia affects about 7% of people in the United States and 0.5–2.5% of people in the rest of the world. Agoraphobia affects about 1.7% of people. Women are affected about twice as often as men. Typically onset is around the age of 10 to 17. Rates become lower as people get older. People with phobias are at a higher risk of suicide.
Classification
Most phobias are classified into three categories and, according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V), such phobias are considered sub-types of anxiety disorder. The categories are:
1. Specific phobias:
Fear of particular objects or social situations that immediately
results in anxiety and can sometimes lead to panic attacks. Specific
phobia may be further subdivided into four categories: animal type,
natural environment type, situational type, blood-injection-injury type.
2. Agoraphobia: a generalized fear of leaving home or a small familiar 'safe' area, and of possible panic attacks
that might follow. It may also be caused by various specific phobias
such as fear of open spaces, social embarrassment (social agoraphobia),
fear of contamination (fear of germs, possibly complicated by obsessive-compulsive disorder) or PTSD (post traumatic stress disorder) related to a trauma that occurred out of doors.
3. Social phobia, also known as social anxiety disorder, is when the situation is feared as the person is worried about others judging them.
Phobias vary in severity among individuals. Some individuals can
simply avoid the subject of their fear and suffer relatively mild
anxiety over that fear. Others suffer full-fledged panic attacks with
all the associated disabling symptoms. Most individuals understand that
they are suffering from an irrational fear, but are powerless to
override their panic reaction. These individuals often report dizziness,
loss of bladder or bowel control, tachypnea, feelings of pain, and shortness of breath.
Specific phobias
A
specific phobia is a marked and persistent fear of an object or
situation. Specific phobias may also include fear of losing control,
panicking, and fainting from an encounter with the phobia.
Specific phobias are defined in relation to objects or situations
whereas social phobias emphasize social fear and the evaluations that
might accompany them.
The DSM breaks specific phobias into five subtypes: animal, natural environment, blood-injection-injury, situation and others. In children, blood-injection-injury phobia
and phobias involving animals, natural environment (darkness) usually
develop between the ages of 7 and 9, and these are reflective of normal
development. Additionally, specific phobias are most prevalent in
children between ages 10 and 13.
Social phobia
Unlike specific phobias, social phobias include fear of public
situations and scrutiny, which leads to embarrassment or humiliation in
the diagnostic criteria.
Causes
Environmental
Rachman
proposed three pathways to acquiring fear conditioning: classical
conditioning, vicarious acquisition and informational/instructional
acquisition.
Much of the progress in understanding the acquisition of fear responses in phobias can be attributed to classical conditioning (Pavlovian model).
When an aversive stimulus and a neutral one are paired together, for
instance when an electric shock is given in a specific room, the subject
can start to fear not only the shock but the room as well. In
behavioral terms, this is described as a conditioned stimulus (CS) (the room) that is paired with an aversive unconditioned stimulus (UCS) (the shock), which leads to a conditioned response (CR) (fear for the room) (CS+UCS=CR).
For instance, in case of the fear of heights (acrophobia), the CS is
heights such as a balcony on the top floors of a high rise building. The
UCS originates from an aversive or traumatizing event in the person's
life, such as almost falling down from a great height. The original fear
of almost falling down is associated with being in a high place,
leading to a fear of heights. In other words, the CS (heights) associated with the aversive UCS (almost falling down) leads to the CR (fear).
This direct conditioning model, though very influential in the theory of
fear acquisition, is not the only way to acquire a phobia.
Vicarious fear acquisition is learning to fear something, not by a
subject's own experience of fear, but by watching others reacting
fearfully (observational learning). For instance, when a child sees a parent reacting fearfully to an animal, the child can become afraid of the animal as well.
Through observational learning, humans can to learn to fear potentially
dangerous objects—a reaction also observed in other primates.
In a study focusing on non-human primates, results showed that the
primates learned to fear snakes at a fast rate after observing parents’
fearful reactions. An increase of fearful behaviours was observed as the non-human primates continued to observe their parents’ fearful reaction.
Even though observational learning has been proven effective in
creating reactions of fear and phobias, it has also been shown that by
physically experiencing an event, chances increase of fearful and phobic
behaviours.
In some cases, physically experiencing an event may increase the fear
and phobia more so than observing a fearful reaction of another human or
non-human primate.
Informational/instructional fear acquisition is learning to fear
something by getting information. For instance, fearing electrical wire
after having heard that touching it causes an electric shock.
A conditioned fear response to an object or situation is not
always a phobia. To meet the criteria for a phobia there must also be
symptoms of impairment and avoidance. Impairment is defined as being
unable to complete routine tasks whether occupational, academic or
social. In acrophobia, an impairment of occupation could result from not
taking a job solely because of its location at the top floor of a
building, or socially not participating in a social event at a theme
park. The avoidance aspect is defined as behaviour that results in the
omission of an aversive event that would otherwise occur, with the goal
of preventing anxiety.
Mechanism
Regions of the brain associated with phobias
Beneath the lateral fissure in the cerebral cortex, the insula, or insular cortex, of the brain has been identified as part of the limbic system, along with cingulated gyrus, hippocampus, corpus callosum and other nearby cortices. This system has been found to play a role in emotion processing and the insula, in particular, may contribute through its role in maintaining autonomic functions.
Studies by Critchley et al. indicate the insula as being involved in
the experience of emotion by detecting and interpreting threatening
stimuli.
Similar studies involved in monitoring the activity of the insula show a
correlation between increased insular activation and anxiety.
In the frontal lobes, other cortices involved with phobia and fear are the anterior cingulate cortex and the medial prefrontal cortex.
In the processing of emotional stimuli, studies on phobic reactions to
facial expressions have indicated that these areas are involved in
processing and responding to negative stimuli. The ventromedial prefrontal cortex has been said to influence the amygdala by monitoring its reaction to emotional stimuli or even fearful memories. Most specifically, the medial prefrontal cortex
is active during extinction of fear and is responsible for long-term
extinction. Stimulation of this area decreases conditioned fear
responses, so its role may be in inhibiting the amygdala and its
reaction to fearful stimuli.
The hippocampus is a horseshoe-shaped structure that plays an important part in the brain's limbic system
because of its role in forming memories and connecting them with
emotions and the senses. When dealing with fear, the hippocampus
receives impulses from the amygdala that allow it to connect the fear
with a certain sense, such as a smell or sound.
Amygdala
The amygdala
is an almond-shaped mass of nuclei that is located deep in the brain's
medial temporal lobe. It processes the events associated with fear and
is linked to social phobia and other anxiety disorders. The amygdala's ability to respond to fearful stimuli occurs through the process of fear conditioning. Similar to classical conditioning,
the amygdala learns to associate a conditioned stimulus with a negative
or avoidant stimulus, creating a conditioned fear response that is
often seen in phobic individuals. In this way, the amygdala is
responsible for not only recognizing certain stimuli or cues as
dangerous but plays a role in the storage of threatening stimuli to
memory. The basolateral nuclei (or basolateral amygdala)
and the hippocampus interact with the amygdala in the storage of
memory, which suggests why memories are often remembered more vividly if
they have emotional significance.
In addition to memory, the amygdala also triggers the secretion of hormones that affect fear and aggression.
When the fear or aggression response is initiated, the amygdala
releases hormones into the body to put the human body into an "alert"
state, which prepares the individual to move, run, fight, etc. This defensive "alert" state and response are known as the fight-or-flight response.
Inside the brain, however, this stress response can be observed in the hypothalamic-pituitary-adrenal axis
(HPA). This circuit incorporates the process of receiving stimuli,
interpreting it and releasing certain hormones into the bloodstream. The
parvocellular neurosecretory neurons of the hypothalamus release corticotropin-releasing hormone (CRH), which is sent to the anterior pituitary. Here the pituitary releases adrenocorticotropic hormone (ACTH), which ultimately stimulates the release of cortisol.
In relation to anxiety, the amygdala is responsible for activating this
circuit, while the hippocampus is responsible for suppressing it. Glucocorticoid
receptors in the hippocampus monitor the amount of cortisol in the
system and through negative feedback can tell the hypothalamus to stop
releasing CRH.
Studies on mice engineered to have high concentrations of CRH
showed higher levels of anxiety, while those engineered to have no or
low amounts of CRH receptors were less anxious. In people with phobias,
therefore, high amounts of cortisol may be present, or alternatively,
there may be low levels of glucocorticoid receptors or even serotonin (5-HT).
Disruption by damage
For
the areas in the brain involved in emotion—most specifically fear— the
processing and response to emotional stimuli can be significantly
altered when one of these regions becomes lesioned or damaged. Damage to
the cortical areas involved in the limbic system such as the cingulate
cortex or frontal lobes have resulted in extreme changes in emotion. Other types of damage include Klüver–Bucy syndrome and Urbach–Wiethe disease.
In Klüver–Bucy syndrome, a temporal lobectomy, or removal of the
temporal lobes, results in changes involving fear and aggression.
Specifically, the removal of these lobes results in decreased fear,
confirming its role in fear recognition and response. Bilateral damage
to the medial temporal lobes, which is known as Urbach–Wiethe disease,
exhibits similar symptoms of decreased fear and aggression, but also an
inability to recognize emotional expressions, especially angry or
fearful faces.
The amygdala's role in learned fear includes interactions with
other brain regions in the neural circuit of fear. While lesions in the
amygdala can inhibit its ability to recognize fearful stimuli, other
areas such as the ventromedial prefrontal cortex and the basolateral
nuclei of the amygdala can affect the region's ability to not only
become conditioned to fearful stimuli but to eventually extinguish them.
The basolateral nuclei, through receiving stimulus info, undergo
synaptic changes that allow the amygdala to develop a conditioned
response to fearful stimuli. Lesions in this area, therefore, have been
shown to disrupt the acquisition of learned responses to fear.
Likewise, lesions in the ventromedial prefrontal cortex (the area
responsible for monitoring the amygdala) have been shown to not only
slow down the speed of extinguishing a learned fear response but also
how effective or strong the extinction is. This suggests there is a
pathway or circuit among the amygdala and nearby cortical areas that
process emotional stimuli and influence emotional expression, all of
which can be disrupted when an area becomes damaged.
Diagnosis
It is recommended that the terms distress and impairment
take into account the context of the person's environment during
diagnosis. The DSM-IV-TR states that if a feared stimulus, whether it be
an object or a social situation, is absent entirely in an environment, a
diagnosis cannot be made. An example of this situation would be an
individual who has a fear of mice
but lives in an area devoid of mice. Even though the concept of mice
causes marked distress and impairment within the individual, because the
individual does not usually encounter mice, no actual distress or
impairment is ever experienced. It is recommended that proximity to, and
ability to escape from, the stimulus also be considered. As the phobic
person approaches a feared stimulus, anxiety levels increase, and the
degree to which the person perceives they might escape from the stimulus
affects the intensity of fear in instances such as riding an elevator
(e.g. anxiety increases at the midway point between floors and decreases
when the floor is reached and the doors open).
Treatments
There are various methods used to treat phobias. These methods include systematic desensitization, progressive relaxation, virtual reality, modeling, medication and hypnotherapy.
Therapy
Cognitive behavioral therapy
(CBT) can be beneficial by allowing the person to challenge
dysfunctional thoughts or beliefs by being mindful of their own
feelings, with the aim that the person will realize that his or her fear
is irrational. CBT may be conducted in a group setting. Gradual
desensitization treatment and CBT are often successful, provided the
person is willing to endure some discomfort. In one clinical trial, 90% of people were observed to no longer have a phobic reaction after successful CBT treatment.
CBT is also an effective treatment for phobias in children and
adolescents and has been adapted for use with this age. One example of a
CBT program targeted towards children is the Coping Cat.
This treatment program can be used with children between the ages of 7
and 13 to treat social phobia. This program works to decrease negative
thinking, increase problem-solving and provide a functional coping
outlook in the child.
Another CBT program was developed by Ann Marie Albano to treat social
phobia in adolescents. This program has five stages: Psychoeducation,
Skill Building, Problem Solving, Exposure and Generalization and
Maintenance. Psychoeducation focuses on identifying and understanding
the symptoms. Skill Building focuses on learning cognitive
restructuring, social skills and problem-solving skills. Problem Solving
focuses on identifying problems and using a proactive approach to
solving them. Exposure involves exposing the adolescent to social
situations in a hierarchical approach. Finally, Generalization and
Maintenance involves practising the skills learned.
Peer-reviewed clinical trials have demonstrated that eye movement desensitization and reprocessing (EMDR) is effective in treating some phobias. Mainly used to treat post-traumatic stress disorder,
EMDR has been demonstrated as effective in easing phobia symptoms
following a specific trauma, such as a fear of dogs following a dog
bite.
Another method used to treat people with extreme phobias is
prolonged exposure, in which the person is exposed to the object of
their fear over a long period of time. This technique is only tested
when a person has overcome avoidance of, or escape from, the feared
object or situation. People with slight distress from their phobias
usually do not need prolonged exposure to their fear.
Systematic desensitization
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A soldier stomping his foot to put out the fire rising up his leg during military fire-phobia training
A method used in the treatment of a phobia is systematic desensitization,
a process in which the people seeking help slowly become accustomed to
their phobia, and ultimately overcome it. Traditional systematic
desensitization involves a person being exposed to the object they are
afraid of overtime, so that the fear and discomfort do not become
overwhelming. This controlled exposure to the anxiety-provoking stimulus
is key to the effectiveness of exposure therapy
in the treatment of specific phobias. It has been shown that humor is
an excellent alternative when traditional systematic desensitization is
ineffective.
Humor systematic desensitization involves a series of treatment
activities that consist of activities that elicit humor with the feared
object.
Previously learned progressive muscle relaxation procedures can be used
as the activities become more difficult in a person's own hierarchy
level. Progressive muscle relaxation helps people relax their muscles
before and during exposure to the feared object or phenomenon.
Participant modeling, in which the therapist models how the
person should respond to fears, has been proven effective for children
and adolescents.
This encourages people to practice the behaviour and reinforces their
efforts. In a manner similar to systematic desensitization, people with
phobias are gradually introduced to their feared objects. The main
difference between participant modelling and systematic desensitization
involves observations and modelling; participant modelling encompasses a
therapist modelling and observing positive behaviours over the course
of gradual exposure to the feared object.
Virtual reality therapy is another technique that helps phobic people confront a feared object. It uses virtual reality
to generate scenes that may not have been possible or ethical in the
physical world. It offers some advantages over systematic
desensitization therapy. People can control the scenes and endure more
exposure than they might handle in reality. Virtual reality is more
realistic than simply imagining a scene—the therapy occurs in a private
room and the treatment is efficient.
Medications
Medications
can help regulate apprehension and fear of a particular fearful object
or situation. Antidepressant medications such as SSRIs or MAOIs
may be helpful in some cases of phobia. SSRIs (antidepressants) act on
serotonin, a neurotransmitter in the brain. Since serotonin impacts
mood, people may be prescribed an antidepressant. Sedatives such as benzodiazepines may also be prescribed, which can help people relax by reducing the amount of anxiety they feel.
Benzodiazepines may be useful in acute treatment of severe symptoms,
but the risk-benefit ratio is against their long-term use in phobic
disorders. This class of medication has recently been shown as effective if used with negative behaviours such as alcohol abuse. Despite this positive finding, benzodiazepines are used with caution. Beta blockers
are another medicinal option as they may stop the stimulating effects
of adrenaline, such as sweating, increased heart rate, elevated blood
pressure, tremors and the feeling of a pounding heart. By taking beta-blockers before a phobic event, these symptoms are decreased, making the event less frightening.
Hypnotherapy
Hypnotherapy can be used alone and in conjunction with systematic desensitization to treat phobias.
Through hypnotherapy, the underlying cause of the phobia may be
uncovered. The phobia may be caused by a past event that the person does
not remember, a phenomenon known as repression. The mind represses
traumatic memories from the conscious mind until the person is ready to
deal with them. Hypnotherapy may also eliminate the conditioned
responses that occur during different situations. People are first
placed into a hypnotic trance, an extremely relaxed state
in which the unconscious can be retrieved. This state makes people more
open to suggestion, which helps bring about desired change. Consciously addressing old memories helps individuals understand the event and see it in a less threatening light.
Epidemiology
Phobias are a common form of anxiety disorder, and distributions are heterogeneous by age and gender. An American study by the National Institute of Mental Health (NIMH) found that between 8.7 percent and 18.1 percent of Americans suffer from phobias, making it the most common mental illness
among women in all age groups and the second most common illness among
men older than 25. Between 4 percent and 10 percent of all children
experience specific phobias during their lives, and social phobias occur in one percent to three percent of children and adolescents.
A Swedish study found that females have a higher number of cases
per year than males (26.5 percent for females and 12.4 percent for
males).
Among adults, 21.2 percent of women and 10.9 percent of men have a
single specific phobia, while multiple phobias occur in 5.4 percent of
females and 1.5 percent of males.
Women are nearly four times as likely as men to have a fear of animals
(12.1 percent in women and 3.3 percent in men) — a higher dimorphic than
with all specific or generalized phobias or social phobias. Social phobias are more common in girls than in boys, while situational phobia occurs in 17.4 percent of women and 8.5 percent of men.
Society and culture
Terminology
The word phobia comes from the Greek: φόβος (phóbos),
meaning "aversion", "fear" or "morbid fear". The regular system for
naming specific phobias to use prefix based on a Greek word for the
object of the fear, plus the suffix -phobia. However, there are many phobias irregularly named with Latin prefixes, such as apiphobia instead of melissaphobia (fear of bees) or aviphobia instead of ornithophobia (fear of birds). Creating these terms is something of a word game. Such fears are psychological rather than physiological in origin and few of these terms are found in medical literature. In ancient Greek mythology Phobos was the twin brother of Deimos (terror).
The word phobia may also refer to conditions other than true phobias. For example, the term hydrophobia is an old name for rabies, since an aversion to water is one of that disease's symptoms. A specific phobia to water is called aquaphobia instead. A hydrophobe is a chemical compound that repels water. Similarly, the term photophobia
usually refers to a physical complaint (aversion to light due to
inflamed eyes or excessively dilated pupils), rather than an irrational
fear of light.
Non-medical use
A number of terms with the suffix -phobia are used non-clinically to imply irrational fear or hatred. Examples include:
- Chemophobia – Negative attitudes and mistrust towards chemistry and synthetic chemicals.
- Xenophobia – Fear or dislike of strangers or the unknown, sometimes used to describe nationalistic political beliefs and movements.
- Homophobia – Negative attitudes and feelings toward homosexuality or people who are identified or perceived as being lesbian, gay, bisexual or transgender (LGBT).
Usually these kinds of "phobias" are described as fear, dislike, disapproval, prejudice, hatred, discrimination or hostility towards the object of the "phobia".
