Coronary artery disease

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Coronary_artery_disease 

 

Coronary artery disease
Other names	Atherosclerotic heart disease, atherosclerotic vascular disease, coronary heart disease
Illustration depicting atherosclerosis in a coronary artery
Specialty	Cardiology, cardiac surgery
Symptoms	Chest pain, shortness of breath
Complications	Heart failure, abnormal heart rhythms, myocardial infarction (heart attack), cardiogenic shock, cardiac arrest
Causes	Atherosclerosis of the arteries of the heart
Risk factors	High blood pressure, smoking, diabetes, lack of exercise, obesity, high blood cholesterol
Diagnostic method	Electrocardiogram, cardiac stress test, coronary computed tomographic angiography, coronary angiogram
Prevention	Healthy diet, regular exercise, maintaining a healthy weight, not smoking
Treatment	Percutaneous coronary intervention (PCI), coronary artery bypass surgery (CABG)
Medication	Aspirin, beta blockers, nitroglycerin, statins
Frequency	110 million (2015)
Deaths	8.9 million (2015)

Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), or simply heart disease, involves the reduction of blood flow to the heart muscle due to build-up of plaque (atherosclerosis) in the arteries of the heart. It is the most common of the cardiovascular diseases. Types include stable angina, unstable angina, myocardial infarction, and sudden cardiac death. A common symptom is chest pain or discomfort which may travel into the shoulder, arm, back, neck, or jaw. Occasionally it may feel like heartburn. Usually symptoms occur with exercise or emotional stress, last less than a few minutes, and improve with rest. Shortness of breath may also occur and sometimes no symptoms are present. In many cases, the first sign is a heart attack. Other complications include heart failure or an abnormal heartbeat.

Risk factors include high blood pressure, smoking, diabetes, lack of exercise, obesity, high blood cholesterol, poor diet, depression, and excessive alcohol. A number of tests may help with diagnoses including: electrocardiogram, cardiac stress testing, coronary computed tomographic angiography, and coronary angiogram, among others.

Ways to reduce CAD risk include eating a healthy diet, regularly exercising, maintaining a healthy weight, and not smoking. Medications for diabetes, high cholesterol, or high blood pressure are sometimes used. There is limited evidence for screening people who are at low risk and do not have symptoms. Treatment involves the same measures as prevention. Additional medications such as antiplatelets (including aspirin), beta blockers, or nitroglycerin may be recommended. Procedures such as percutaneous coronary intervention (PCI) or coronary artery bypass surgery (CABG) may be used in severe disease. In those with stable CAD it is unclear if PCI or CABG in addition to the other treatments improves life expectancy or decreases heart attack risk.

In 2015, CAD affected 110 million people and resulted in 8.9 million deaths. It makes up 15.6% of all deaths, making it the most common cause of death globally. The risk of death from CAD for a given age decreased between 1980 and 2010, especially in developed countries. The number of cases of CAD for a given age also decreased between 1990 and 2010. In the United States in 2010, about 20% of those over 65 had CAD, while it was present in 7% of those 45 to 64, and 1.3% of those 18 to 45; rates were higher among men than women of a given age.

Clogged artery

Signs and symptoms

The narrowing of coronary arteries reduces the supply of oxygen-rich blood flowing to the heart, which becomes more pronounced during strenuous activities during which the heart beats faster. For some, this causes severe symptoms while others experience no symptoms at all.

The most common symptom is chest pain or discomfort that occurs regularly with activity, after eating, or at other predictable times; this phenomenon is termed stable angina and is associated with narrowing of the arteries of the heart. Angina also includes chest tightness, heaviness, pressure, numbness, fullness, or squeezing. Angina that changes in intensity, character or frequency is termed unstable. Unstable angina may precede myocardial infarction. In adults who go to the emergency department with an unclear cause of pain, about 30% have pain due to coronary artery disease. Angina, shortness of breath, sweating, nausea or vomiting, and lightheadedness are signs of a heart attack, or myocardial infarction, and immediate emergency medical services are crucial.

Symptoms in women

Further information: Cardiovascular disease in women

Symptoms in women can differ from those in men, and the most common symptom reported by women of all races is shortness of breath. Other symptoms more commonly reported by women than men are extreme fatigue, sleep disturbances, indigestion, and anxiety. However, some women do experience irregular heartbeat, dizziness, sweating, and nausea. Burning, pain, or pressure in the chest or upper abdomen that can travel to the arm or jaw can also be experienced in women, but it is less commonly reported by women than men. On average, women experience symptoms 10 years later than men. Women are less likely to recognize symptoms and seek treatment.

Risk factors

Coronary artery disease has a number of well determined risk factors. These include high blood pressure, smoking, diabetes, lack of exercise, obesity, high blood cholesterol, poor diet, depression, family history, and excessive alcohol. About half of cases are linked to genetics. Smoking and obesity are associated with about 36% and 20% of cases, respectively. Smoking just one cigarette per day about doubles the risk of CAD. Lack of exercise has been linked to 7–12% of cases. Exposure to the herbicide Agent Orange may increase risk. Rheumatologic diseases such as rheumatoid arthritis, systemic lupus erythematosus, psoriasis, and psoriatic arthritis are independent risk factors as well.

Job stress appears to play a minor role accounting for about 3% of cases. In one study, women who were free of stress from work life saw an increase in the diameter of their blood vessels, leading to decreased progression of atherosclerosis. In contrast, women who had high levels of work-related stress experienced a decrease in the diameter of their blood vessels and significantly increased disease progression. Having a type A behavior pattern, a group of personality characteristics including time urgency, competitiveness, hostility, and impatience, is linked to an increased risk of coronary disease.

Blood fats

• High blood cholesterol (specifically, serum LDL concentrations). HDL (high density lipoprotein) has a protective effect over development of coronary artery disease.
• High blood triglycerides may play a role.
• High levels of lipoprotein(a), a compound formed when LDL cholesterol combines with a protein known as apolipoprotein(a).

Dietary cholesterol does not appear to have a significant effect on blood cholesterol and thus recommendations about its consumption may not be needed. Saturated fat is still a concern.

Genetics

The heritability of coronary artery disease has been estimated between 40% and 60%. Genome-wide association studies have identified over 160 genetic susceptibility loci for coronary artery disease.

Other

• Endometriosis in women under the age of 40.
• Depression and hostility appear to be risks.
• The number of categories of adverse childhood experiences (psychological, physical, or sexual abuse; violence against mother; or living with household members who used substances, mentally ill, suicidal, or incarcerated) showed a graded correlation with the presence of adult diseases including coronary artery (ischemic heart) disease.
• Hemostatic factors: High levels of fibrinogen and coagulation factor VII are associated with an increased risk of CAD.
• Low hemoglobin.
• In the Asian population, the b fibrinogen gene G-455A polymorphism was associated with the risk of CAD.

Pathophysiology

Micrograph of a coronary artery with the most common form of coronary artery disease (atherosclerosis) and marked luminal narrowing. Masson's trichrome.

 

Illustration depicting coronary artery disease

Limitation of blood flow to the heart causes ischemia (cell starvation secondary to a lack of oxygen) of the heart's muscle cells. The heart's muscle cells may die from lack of oxygen and this is called a myocardial infarction (commonly referred to as a heart attack). It leads to damage, death, and eventual scarring of the heart muscle without regrowth of heart muscle cells. Chronic high-grade narrowing of the coronary arteries can induce transient ischemia which leads to the induction of a ventricular arrhythmia, which may terminate into a dangerous heart rhythm known as ventricular fibrillation, which often leads to death.

Typically, coronary artery disease occurs when part of the smooth, elastic lining inside a coronary artery (the arteries that supply blood to the heart muscle) develops atherosclerosis. With atherosclerosis, the artery's lining becomes hardened, stiffened, and accumulates deposits of calcium, fatty lipids, and abnormal inflammatory cells – to form a plaque. Calcium phosphate (hydroxyapatite) deposits in the muscular layer of the blood vessels appear to play a significant role in stiffening the arteries and inducing the early phase of coronary arteriosclerosis. This can be seen in a so-called metastatic mechanism of calciphylaxis as it occurs in chronic kidney disease and hemodialysis. Although these people suffer from kidney dysfunction, almost fifty percent of them die due to coronary artery disease. Plaques can be thought of as large "pimples" that protrude into the channel of an artery, causing partial obstruction to blood flow. People with coronary artery disease might have just one or two plaques, or might have dozens distributed throughout their coronary arteries. A more severe form is chronic total occlusion (CTO) when a coronary artery is completely obstructed for more than 3 months.

Cardiac syndrome X is chest pain (angina pectoris) and chest discomfort in people who do not show signs of blockages in the larger coronary arteries of their hearts when an angiogram (coronary angiogram) is being performed. The exact cause of cardiac syndrome X is unknown. Explanations include microvascular dysfunction or epicardial atherosclerosis. For reasons that are not well understood, women are more likely than men to have it; however, hormones and other risk factors unique to women may play a role.

Diagnosis

Coronary angiogram of a man

 

Coronary angiogram of a woman

For symptomatic people, stress echocardiography can be used to make a diagnosis for obstructive coronary artery disease. The use of echocardiography, stress cardiac imaging, and/or advanced non-invasive imaging is not recommended on individuals who are exhibiting no symptoms and are otherwise at low risk for developing coronary disease.

The diagnosis of "Cardiac Syndrome X" – the rare coronary artery disease that is more common in women, as mentioned, is a diagnosis of exclusion. Therefore, usually, the same tests are used as in any person with the suspected of having coronary artery disease:

• Baseline electrocardiography (ECG)
• Exercise ECG – Stress test
• Exercise radioisotope test (nuclear stress test, myocardial scintigraphy)
• Echocardiography (including stress echocardiography)
• Coronary angiography
• Intravascular ultrasound
• Magnetic resonance imaging (MRI)

The diagnosis of coronary disease underlying particular symptoms depends largely on the nature of the symptoms. The first investigation is an electrocardiogram (ECG/EKG), both for "stable" angina and acute coronary syndrome. An X-ray of the chest and blood tests may be performed.

Stable angina

Main article: Angina pectoris

In "stable" angina, chest pain with typical features occurring at predictable levels of exertion, various forms of cardiac stress tests may be used to induce both symptoms and detect changes by way of electrocardiography (using an ECG), echocardiography (using ultrasound of the heart) or scintigraphy (using uptake of radionuclide by the heart muscle). If part of the heart seems to receive an insufficient blood supply, coronary angiography may be used to identify stenosis of the coronary arteries and suitability for angioplasty or bypass surgery.

Stable coronary artery disease (SCAD) is also often called stable ischemic heart disease (SIHD). A 2015 monograph explains that "Regardless of the nomenclature, stable angina is the chief manifestation of SIHD or SCAD." There are U.S. and European clinical practice guidelines for SIHD/SCAD.

Acute coronary syndrome

Main article: Acute coronary syndrome

Diagnosis of acute coronary syndrome generally takes place in the emergency department, where ECGs may be performed sequentially to identify "evolving changes" (indicating ongoing damage to the heart muscle). Diagnosis is clear-cut if ECGs show elevation of the "ST segment", which in the context of severe typical chest pain is strongly indicative of an acute myocardial infarction (MI); this is termed a STEMI (ST-elevation MI) and is treated as an emergency with either urgent coronary angiography and percutaneous coronary intervention (angioplasty with or without stent insertion) or with thrombolysis ("clot buster" medication), whichever is available. In the absence of ST-segment elevation, heart damage is detected by cardiac markers (blood tests that identify heart muscle damage). If there is evidence of damage (infarction), the chest pain is attributed to a "non-ST elevation MI" (NSTEMI). If there is no evidence of damage, the term "unstable angina" is used. This process usually necessitates hospital admission and close observation on a coronary care unit for possible complications (such as cardiac arrhythmias – irregularities in the heart rate). Depending on the risk assessment, stress testing or angiography may be used to identify and treat coronary artery disease in patients who have had an NSTEMI or unstable angina.

Risk assessment

There are various risk assessment systems for determining the risk of coronary artery disease, with various emphasis on different variables above. A notable example is Framingham Score, used in the Framingham Heart Study. It is mainly based on age, gender, diabetes, total cholesterol, HDL cholesterol, tobacco smoking, and systolic blood pressure. When it comes to predicting risk in younger adults (18–39 years old), Framingham Risk Score remains below 10-12% for all deciles of baseline-predicted risk.

Polygenic score is another way of risk assessment. In one study the relative risk of incident coronary events was 91% higher among participants at high genetic risk than among those at low genetic risk.

Prevention

Up to 90% of cardiovascular disease may be preventable if established risk factors are avoided. Prevention involves adequate physical exercise, decreasing obesity, treating high blood pressure, eating a healthy diet, decreasing cholesterol levels, and stopping smoking. Medications and exercise are roughly equally effective. High levels of physical activity reduce the risk of coronary artery disease by about 25%.

Most guidelines recommend combining these preventive strategies. A 2015 Cochrane Review found some evidence that counseling and education to bring about behavioral change might help in high-risk groups. However, there was insufficient evidence to show an effect on mortality or actual cardiovascular events.

In diabetes mellitus, there is little evidence that very tight blood sugar control improves cardiac risk although improved sugar control appears to decrease other problems such as kidney failure and blindness. The World Health Organization (WHO) recommends "low to moderate alcohol intake" to reduce risk of coronary artery disease while high intake increases the risk.

Diet

Main article: Diet and heart disease

A diet high in fruits and vegetables decreases the risk of cardiovascular disease and death. Vegetarians have a lower risk of heart disease, possibly due to their greater consumption of fruits and vegetables. Evidence also suggests that the Mediterranean diet and a high fiber diet lower the risk.

The consumption of trans fat (commonly found in hydrogenated products such as margarine) has been shown to cause a precursor to atherosclerosis and increase the risk of coronary artery disease.

Evidence does not support a beneficial role for omega-3 fatty acid supplementation in preventing cardiovascular disease (including myocardial infarction and sudden cardiac death). There is tentative evidence that intake of menaquinone (Vitamin K₂), but not phylloquinone (Vitamin K₁), may reduce the risk of CAD mortality.

Secondary prevention

Secondary prevention is preventing further sequelae of already established disease. Effective lifestyle changes include:

• Weight control
• Smoking cessation
• Avoiding the consumption of trans fats (in partially hydrogenated oils)
• Decreasing psychosocial stress
• Exercise

Aerobic exercise, like walking, jogging, or swimming, can reduce the risk of mortality from coronary artery disease. Aerobic exercise can help decrease blood pressure and the amount of blood cholesterol (LDL) over time. It also increases HDL cholesterol which is considered "good cholesterol".

Although exercise is beneficial, it is unclear whether doctors should spend time counseling patients to exercise. The U.S. Preventive Services Task Force found "insufficient evidence" to recommend that doctors counsel patients on exercise but "it did not review the evidence for the effectiveness of physical activity to reduce chronic disease, morbidity, and mortality", only the effectiveness of counseling itself. The American Heart Association, based on a non-systematic review, recommends that doctors counsel patients on exercise.

Psychological symptoms are common in people with CHD, and while many psychological treatments may be offered following cardiac events, there is no evidence that they change mortality, the risk of revascularization procedures, or the rate of non-fatal myocardial infarction.

Antibiotics for secondary prevention of coronary heart disease

Antibiotics may help patients with coronary disease to reduce the risk of heart attacks and strokes. However, the latest evidence suggests that antibiotics for secondary prevention of coronary heart disease are harmful with increased mortality and occurrence of stroke. So, the use of antibiotics is not currently supported for preventing secondary coronary heart disease.

Neuropsychological Assessment

A thorough systematic review found that indeed there is a link between a CHD condition and brain dysfunction in females/women. Consequently, since research is showing that cardiovascular diseases, like CHD, can play a role as a precursor for dementia, like Alzheimer's disease, individuals with CHD should have a neuropsychological assessment.

Treatment

There are a number of treatment options for coronary artery disease:

• Lifestyle changes
• Medical treatment – drugs (e.g., cholesterol lowering medications, beta-blockers, nitroglycerin, calcium channel blockers, etc.);
• Coronary interventions as angioplasty and coronary stent;
• Coronary artery bypass grafting (CABG)

Medications

• Statins, which reduce cholesterol, reduce the risk of coronary artery disease
• Nitroglycerin
• Calcium channel blockers and/or beta-blockers
• Antiplatelet drugs such as aspirin

It is recommended that blood pressure typically be reduced to less than 140/90 mmHg. The diastolic blood pressure however should not be lower than 60 mmHg. Beta blockers are recommended first line for this use.

Aspirin

In those with no previous history of heart disease, aspirin decreases the risk of a myocardial infarction but does not change the overall risk of death. It is thus only recommended in adults who are at increased risk for coronary artery disease where increased risk is defined as "men older than 90 years of age, postmenopausal women, and younger persons with risk factors for coronary artery disease (for example, hypertension, diabetes, or smoking) who are at increased risk for heart disease and may wish to consider aspirin therapy". More specifically, high-risk persons are "those with a 5-year risk ≥ 3%".

Anti-platelet therapy

Clopidogrel plus aspirin (dual anti-platelet therapy) reduces cardiovascular events more than aspirin alone in those with a STEMI. In others at high risk but not having an acute event, the evidence is weak. Specifically, its use does not change the risk of death in this group. In those who have had a stent, more than 12 months of clopidogrel plus aspirin does not affect the risk of death.

Surgery

Revascularization for acute coronary syndrome has a mortality benefit. Percutaneous revascularization for stable ischaemic heart disease does not appear to have benefits over medical therapy alone. In those with disease in more than one artery, coronary artery bypass grafts appear better than percutaneous coronary interventions. Newer "anaortic" or no-touch off-pump coronary artery revascularization techniques have shown reduced postoperative stroke rates comparable to percutaneous coronary intervention. Hybrid coronary revascularization has also been shown to be a safe and feasible procedure that may offer some advantages over conventional CABG though it is more expensive.

Epidemiology

Deaths due to ischaemic heart disease per million persons in 2012

  160–288

  289–379

  380–460

  461–576

  577–691

  692–894

  895–1,068

  1,069–1,443

  1,444–2,368

  2,369–7,233

Disability-adjusted life year for ischaemic heart disease per 100,000 inhabitants in 2004.

  no data

  <350

  350–700

  700–1,050

  1,050–1,400

  1,400–1,750

  1,750–2,100

  2,100–2,450

  2,450–2,800

  2,800–3,150

  3,150–3,500

  3,500–4,000

  >4,000

As of 2010, CAD was the leading cause of death globally resulting in over 7 million deaths. This increased from 5.2 million deaths from CAD worldwide in 1990. It may affect individuals at any age but becomes dramatically more common at progressively older ages, with approximately a tripling with each decade of life. Males are affected more often than females.

It is estimated that 60% of the world's cardiovascular disease burden will occur in the South Asian subcontinent despite only accounting for 20% of the world's population. This may be secondary to a combination of genetic predisposition and environmental factors. Organizations such as the Indian Heart Association are working with the World Heart Federation to raise awareness about this issue.

Coronary artery disease is the leading cause of death for both men and women and accounts for approximately 600,000 deaths in the United States every year. According to present trends in the United States, half of healthy 40-year-old men will develop CAD in the future, and one in three healthy 40-year-old women. It is the most common reason for death of men and women over 20 years of age in the United States.

Society and culture

Names

Other terms sometimes used for this condition are "hardening of the arteries" and "narrowing of the arteries". In Latin it is known as morbus ischaemicus cordis (MIC).

Support groups

The Infarct Combat Project (ICP) is an international nonprofit organization founded in 1998 which tries to decrease ischemic heart diseases through education and research.

Industry influence on research

In 2016 research into the archives of the Sugar Association, the trade association for the sugar industry in the US, had sponsored an influential literature review published in 1965 in the New England Journal of Medicine that downplayed early findings about the role of a diet heavy in sugar in the development of CAD and emphasized the role of fat; that review influenced decades of research funding and guidance on healthy eating.

Research

Further information: Atheroma and Atherosclerosis

Research efforts are focused on new angiogenic treatment modalities and various (adult) stem-cell therapies. A region on chromosome 17 was confined to families with multiple cases of myocardial infarction. Other genome-wide studies have identified a firm risk variant on chromosome 9 (9p21.3). However, these and other loci are found in intergenic segments and need further research in understanding how the phenotype is affected.

A more controversial link is that between Chlamydophila pneumoniae infection and atherosclerosis. While this intracellular organism has been demonstrated in atherosclerotic plaques, evidence is inconclusive as to whether it can be considered a causative factor. Treatment with antibiotics in patients with proven atherosclerosis has not demonstrated a decreased risk of heart attacks or other coronary vascular diseases.

Since the 1990s the search for new treatment options for coronary artery disease patients, particularly for so called "no-option" coronary patients, focused on usage of angiogenesis and (adult) stem cell therapies. Numerous clinical trials were performed, either applying protein (angiogenic growth factor) therapies, such as FGF-1 or VEGF, or cell therapies using different kinds of adult stem cell populations. Research is still going on – with first promising results particularly for FGF-1 and utilization of endothelial progenitor cells.

Myeloperoxidase has been proposed as a biomarker.

Plant-based nutrition has been suggested as a way to reverse coronary artery disease, but strong evidence is still lacking for claims of potential benefits.

Attention deficit hyperactivity disorder controversies

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Attention_deficit_hyperactivity_disorder_controversies 

 

Methylphenidate (Ritalin) 10 mg Pill (Ciba/Novartis), a drug commonly prescribed to treat ADHD

Attention deficit hyperactivity disorder (ADHD) controversies include concerns about causes, perceived overdiagnosis, and methods of treatment, especially with the use of stimulant medications in children. While currently the disorder ADHD is widely recognized and accepted, the treatments for the disorder are not. These controversies have surrounded the subject since at least the 1970s. Problems with the treatment of the disorder start with diagnosis, as differences in male and female developments leads to both over and under diagnoses. This has set up controversies in treatment as well. Treatment of ADHD has come into scrutiny due to misuse of stimulants, conflicts of interest and the stigma surrounding mental health diagnoses.

Status as a disorder

According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), the leading authority in the US on clinical diagnosis, ADHD is a neurodevelopmental disorder with a prevalence rate in most cultures of about 5% in children and 2.5% in adults. Today, the existence of ADHD is widely accepted, but controversy around the disorder has existed since at least the 1970s. According to the DSM-5, symptoms must be present before age 12, but it is not uncommon for ADHD to continue into adulthood. Parents and educators sometimes still question a perceived over diagnosis in children due to overlapping symptoms with other mental disabilities, and the effectiveness of treatment options, especially the overprescription of stimulant medications. However, according to sociology professor Vincent Parrillo, "Parent and consumer groups, such as CHADD (Children and Adults with Attention Deficit Hyperactivity Disorder), tend to support the medical perspective of ADHD."

Causes

The pathophysiology of ADHD is unclear and there are a number of competing theories.

ADHD as a biological difference

Frequently observed differences in the brain between ADHD and non-ADHD patients have been discovered, but it is uncertain if or how these differences give rise to the symptoms of ADHD. Results from various types of neuroimaging techniques suggest there are differences in the brain, such as thinner regions of the cortex in individuals with ADHD.

ADHD is said to be highly heritable: twin studies suggest that genetics explain 70-80% in the variation of ADHD. However, interest in the potential role of gene-environment interactions in ADHD is also increasing; maternal alcohol or tobacco use during pregnancy may be one contributor. It has also been argued that ADHD is a heterogeneous disorder with multiple genetic and environmental factors converging on similar neurological changes. Authors of a review of ADHD etiology in 2004 noted: "Although several genome-wide searches have identified chromosomal regions that are predicted to contain genes that contribute to ADHD susceptibility, to date no single gene with a major contribution to ADHD has been identified." However, many further studies have occurred since, and the same is true for many other heritable human traits (e.g., schizophrenia). The Online Mendelian Inheritance in Man (OMIM) database has a listing for ADHD under autosomal dominant heritable conditions, claiming that multiple genes contribute to the disorder. As of 2014, OMIM listed 6 genes with variants that have been associated with ADHD.

Social construct theory of ADHD

Main article: Social construct theory of ADHD

It has been argued that even if it is a social construct, this does not mean it is not a valid condition; for example obesity has different cultural constructs but yet has demonstrable adverse effects associated with it. A minority of these critics maintain that ADHD was "invented and not discovered". They believe that the disorder does not exist and that the behavior observed is not abnormal and can be better explained by environmental causes or just the personality of the "patient".

Diagnosis

Methods of diagnosis

Over the past two decades more research on the functioning of the brain is being done to help support the idea that Attention Deficit Hyperactivity Disorder is an executive dysfunction issue. The brains of males and females are showing differences, which could potentially help to explain why ADHD presents differently in boys and girls. Studies conducted using EEGs between boys and girls suggest that we can no longer ignore sex difference between boys and girls when identifying ADHD. There are EEG differences between girls and boys in their maturational pattern and this suggests that more studies regarding sex differences in ADHD should be conducted. The current way that diagnosis are made is using the DSM-5, along with a possible physical and visual examination.

Over- and under-diagnosis

Overdiagnosis typically refers to children who are diagnosed with ADHD but should not be. These instances are termed as "false positives". However, the "presence of false positives alone does not indicate overdiagnosis". There may be evidence of overdiagnosis if inaccuracies are shown consistently in the accepted prevalence rates or in the diagnostic process itself. "For ADHD to be overdiagnosed, the rate of false positives (i.e., children inappropriately diagnosed with ADHD) must substantially exceed the number of false negatives (children with ADHD who are not identified or diagnosed)." Children aged 8 to 15 years living in the community, indicated an ADHD prevalence rate of 7.8%. However, only 48% of the ADHD sample had received any mental health care over the past 12 months.

Evidence also exists of possible differences of race and ethnicity in the prevalence of ADHD. The prevalence of ADHD dramatically varies across cultures despite the fact that the same methodology has been used. Some believe this may be due to different perceptions of what qualifies as disruptive behavior, inattention and hyperactivity.

It is argued that over-diagnosis occurs more in well-off or more homogeneous communities, whereas under-diagnosis occurs more frequently in poorer and minority communities due to lack of resources and lack of financial access. Those without health insurance are less likely to be diagnosed with ADHD. It is further believed that the "distribution of ADHD diagnosis falls along socioeconomic lines", according to the amount of wealth within a neighborhood. Therefore, the difficulty of applying national, general guidelines to localized and specific contexts, such as where referral is unavailable, resources are lacking or the patient is uninsured, may assist in the establishment of a misdiagnosis of ADHD.

Development can also influence perception of relevant ADHD symptoms. ADHD is viewed as a chronic disorder that develops in childhood and continues into adulthood. However, some research shows a decline in the symptoms of ADHD as children grow up and mature into adulthood. As children move into the stage of adolescence, the most common reporters of ADHD symptoms, parents and teachers, tend to focus on behaviors affecting academic performance. Some research has shown that the primary symptoms of ADHD were strong discriminators in parent ratings, but differed for specific age groups. Hyperactivity was a stronger discriminator of ADHD in children, while inattentiveness was a stronger discriminator in adolescents.

Issues with comorbidity is another possible explanation in favor of the argument of overdiagnosis. As many as 75% of diagnosed children with ADHD meet criteria for some other psychiatric diagnosis. Among children diagnosed with ADHD, about 25% to 30% have anxiety disorders, 9% to 32% have depression, 45% to 84% have oppositional defiant disorder, and 44% to 55% of adolescents have conduct disorder. Learning disorders are found in 20% to 40% of children with ADHD.

Another possible explanation of over-diagnosis of ADHD is the "relative-age effect", which applies to children of both sexes. Younger children are more likely to be inappropriately diagnosed with ADHD and treated with prescription medication than their older peers in the same grade. Children who are almost a year younger tend to appear more immature than their classmates, which influences both their academic and athletic performance.

The debate of underdiagnosis, or giving a "false negative", has also been discussed, specifically in literature concerning ADHD among adults, girls and underprivileged communities. It is estimated that in the adult population, rates of ADHD are somewhere between 4% and 6%. However, as little as 11% of these adults with ADHD actually receive assessment, and furthermore, any form of treatment. Between 30% and 70% of children with ADHD report at least one impairing symptom of ADHD in adulthood, and 30% to 50% still meet diagnostic criteria for an ADHD diagnosis.

Research on gender differences also reveals an argument for underdiagnosis of ADHD among girls. The ratio for male-to-female is 4:1 with 92% of girls with ADHD receiving a primarily inattentive subtype diagnosis. This difference in gender can be explained, for the majority, by the different ways boys and girls express symptoms of this particular disorder. Typically, females with ADHD exhibit less disruptive behaviors and more internalizing behaviors. Girls tend to show fewer behavioral problems, show fewer aggressive behaviors, are less impulsive, and are less hyperactive than boys diagnosed with ADHD. These patterns of behavior are less likely to disrupt the classroom or home setting, therefore allowing parents and teachers to easily overlook or neglect the presence of a potential problem. The current diagnostic criteria appear to be more geared towards males than females, and the ADHD characteristics of men have been over-represented. This leaves many women and girls with ADHD neglected. Studies have shown that girls with ADHD, especially those with signs of impulsivity, were three to four times more likely to attempt suicide when compared with female controls. Additionally, these girls were two to three times more likely to engage in self-harming behaviors.

As stated previously, underdiagnosis is also believed to be seen in more underprivileged communities. These communities tend to be poorer and inhabit more minorities. More than 50% of children with mental health needs do not receive assessment or treatment. Access to mental health services and resources differs on a wide range of factors, such as "gender, age, race or ethnicity and health insurance". Therefore, children deserving of an ADHD diagnosis may never receive this confirmation and are not identified or represented in prevalence rates.

In 2005, 82 percent of teachers in the United States considered ADHD to be over diagnosed while three percent considered it to be under diagnosed. In China 19 percent of teachers considered ADHD to be over diagnosed while 57 percent considered it to be under diagnosed.

Treatment

ADHD management recommendations vary by country and usually involves some combination of counseling, lifestyle changes, and medications. The British guideline only recommends medications as a first-line treatment in children who have severe symptoms and for them to be considered in those with moderate symptoms who either refuse or fail to improve with counseling. Canadian and American guidelines recommend that medications and behavioral therapy be used together as a first-line therapy, except in preschool-aged children.

Stimulants

The National Institute of Mental Health recommends stimulants for the treatment of ADHD, and states that, "under medical supervision, stimulant medications are considered safe". A 2007 drug class review found no evidence of any differences in efficacy or side effects in the stimulants commonly prescribed.

Between 1993 and 2003 the worldwide use of medications that treat ADHD increased almost threefold. Most ADHD medications are prescribed in the United States. In the 1990s, the US accounted for 90% of global use of stimulants such as methylphenidate and dextroamphetamine. By the early 2000s, this had fallen to 80% due to increased usage in other countries. In 2003, doctors in the UK were prescribing about a 10th of the amount per capita of methylphenidate used in the US, while France and Italy accounted for approximately one twentieth of US stimulant consumption. These assertions appear to contradict the 2006 World Drug Report published by the United Nations Office on Drugs and Crime, which indicate the US constituted merely 17% of the world market for dextroamphetamine. They assert that in the early 2000s amphetamine use was "widespread in Europe."

In 1999, a study constructed with 1,285 children and their parents across four U.S. communities has shown 12.5% of children that met ADHD criteria had been treated with stimulants during the previous 12 months. In May 2000, the testimony of DEA Deputy Director Terrance Woodworth has shown that the Ritalin quota increased from 1,768 kg in 1990 to 14,957 kg in 2000. In addition, IMS Health also revealed the number of Adderall prescriptions have increased from 1.3 million in 1996 to nearly 6 million in 1999.

Adverse effects

Some parents and professionals have raised questions about the side effects of drugs and their long-term use. Magnetic resonance imaging studies suggest that long-term treatment with amphetamine or methylphenidate decreases abnormalities in brain structure and function found in subjects with ADHD, and improves function of the right caudate nucleus.

On February 9, 2006, the U.S. Food and Drug Administration voted to recommend a "black-box" warning describing the cardiovascular risks of stimulant drugs used to treat ADHD. Subsequently, the USFDA commissioned studies which found that, in children, young adults, and adults, there is no association between serious adverse cardiovascular events (sudden death, myocardial infarction, and stroke) and the medical use of amphetamine or other ADHD stimulants.

The effects of amphetamine and methylphenidate on gene regulation are both dose- and route-dependent. Most of the research on gene regulation and addiction is based upon animal studies with intravenous amphetamine administration at very high doses. The few studies that have used equivalent (weight-adjusted) human therapeutic doses and oral administration show that these changes, if they occur, are relatively minor. The long-term effects on the developing brain and on mental health disorders in later life of chronic use of methylphenidate is unknown. Despite this, between 0.51% to 1.23% of children between the ages of 2 and 6 years take stimulants in the US. Stimulant drugs are not approved for this age group.

In individuals who experience sub-normal height and weight gains during stimulant therapy, a rebound to normal levels is expected to occur if stimulant therapy is briefly interrupted. The average reduction in final adult height from continuous stimulant therapy over a 3-year period is 2 cm. Amphetamines doubles the risk of psychosis compared to methylphenidate in ADHD patients.

Effectiveness

Reviews of clinical stimulant research have established the safety and effectiveness of long-term amphetamine use for ADHD. An evidence review noted the findings of a randomized controlled trial of amphetamine treatment for ADHD in Swedish children following 9 months of amphetamine use. During treatment, the children experienced improvements in attention, disruptive behaviors, and hyperactivity, and an average change of +4.5 in IQ. It noted that the population in the study had a high rate of comorbid disorders associated with ADHD and suggested that other long-term amphetamine trials in people with fewer associated disorders could find greater functional improvements.

A 2008 review found that the use of stimulants improved teachers' and parents' ratings of behavior; however, it did not improve academic achievement. The same review also indicates growth retardation for children consistently medicated over three years, compared to unmedicated children in the study. Intensive treatment for 14 months has no effect on long-term outcomes 8 years later. No significant differences between the various drugs in terms of efficacy or side effects have been found.

Treatment non-adherence and acceptability

The rates of treatment discontinuation are higher than the rates of ADHD patients that receive no treatment at all; few studies present evidence that adherence to ADHD treatment is occurring at high rates with low acceptability. A literature review on empirical studies from 1997 to 2014 revealed a lack of research on adult non-adherence, however there is a large body of research on children and adolescents who discontinue treatment. Some of the common reasons for stopping treatment includes the idea that it is not needed or does not reduce the symptoms of ADHD, as well as reported adverse drug effects like weight and appetite loss, sleeping difficulties, combined with other medically diagnosed conditions.

Research has shown that adherence and acceptability improvements are possible with accessible and convenient community-based treatment options. Some schools in the United States have attempted to make it mandatory for hyperactive children to receive medication based treatment in order to attend classes, however the United States Senate passed a bill in 2005 against this practice.

Potential for misuse

Stimulants used to treat ADHD are classified as Schedule II controlled substances in the United States.

Controversy has surrounded whether methylphenidate is as commonly abused as other stimulants with many proposing that its rate of abuse is much lower than other stimulants. However, the majority of studies assessing its abuse potential scores have determined that it has an abuse potential similar to that of cocaine and d-amphetamine.

Both children with and without ADHD abuse stimulants, with ADHD individuals being at the highest risk of abusing or diverting their stimulant prescriptions. Between 16 and 29 percent of students who are prescribed stimulants report diverting their prescriptions. Between 5 and 9 percent of grade/primary and high school children and between 5 and 35 percent of college students have used nonprescribed stimulants. Most often their motivation is to concentrate, improve alertness, "get high," or to experiment.

Stimulant medications may be resold by patients as recreational drugs, and methylphenidate (Ritalin) is used as a study aid by some students without ADHD.

Non-medical prescription stimulant use is high. A 2003 study found that non prescription use within the last year by college students in the US was 4.1%. A 2008 meta analysis found even higher rates of non prescribed stimulant use. It found 5% to 9% of grade school and high school children and 5% to 35% of college students used a nonprescribed stimulant in the last year.

As of 2009, 8% of all United States Major League Baseball players had been diagnosed with ADHD, making the disorder common among this population. The increase coincided with the League's 2006 ban on stimulants, which has raised concern that some players are mimicking or falsifying the symptoms or history of ADHD to get around the ban on the use of stimulants in sport.

Conflicts of interest

In 2008 five pharmaceutical companies received warning from the FDA regarding false advertising and inappropriate professional slide decks related to ADHD medication. In September 2008 the FDA sent notices to Novartis Pharmaceuticals and Johnson & Johnson regarding advertisings of Focalin XR and Concerta in which they overstated products' efficacies. A similar warning was sent to Shire plc with respect to Adderall XR.

Russell Barkley, a well-known ADHD researcher who has published diagnostic guidelines, has been criticized for his works because he received payment from pharmaceutical companies for speaking and consultancy fees.

In 2008, it was revealed that Joseph Biederman of Harvard, a frequently cited ADHD expert, failed to report to Harvard that he had received $1.6 million from pharmaceutical companies between 2000 and 2007. E. Fuller Torrey, executive director of the Stanley Medical Research Institute which finances psychiatric studies, said "In the area of child psychiatry in particular, we know much less than we should, and we desperately need research that is not influenced by industry money."

Children and Adults with Attention-Deficit/Hyperactivity Disorder, CHADD, an ADHD advocacy group based in Landover, MD received a total of $1,169,000 in 2007 from pharmaceutical companies. These donations made up 26 percent of their budget.

Stigma

Russell Barkley believes labeling is a double-edged sword; there are many pitfalls to labeling but by using a precise label, services can be accessed. He also believes that labeling can help the individual understand and make an informed decision how best to deal with the diagnoses using evidence-based knowledge. Studies also show that the education of the siblings and parents has at least a short-term impact on the outcome of treatment. Barkley states this about ADHD rights: "... because of various legislation that has been passed to protect them. There are special education laws with the Americans with Disabilities Act, for example, mentioning ADHD as an eligible condition. If you change the label, and again refer to it as just some variation in normal temperament, these people will lose access to these services, and will lose these hard-won protections that keep them from being discriminated against. ..." Psychiatrist Harvey Parker, who founded CHADD, states, "we should be celebrating the fact that school districts across the country are beginning to understand and recognize kids with ADHD, and are finding ways of treating them. We should celebrate the fact that the general public doesn't look at ADHD kids as "bad" kids, as brats, but as kids who have a problem that they can overcome". However, children may be ridiculed at school by their peers for using psychiatric medications including those for ADHD.

Perspectives on ADHD

Medical perspectives outside of North America

In 2009, the British Psychological Society and the Royal College of Psychiatrists, in collaboration with the National Institute for Clinical Excellence (NICE), released a set of diagnosis and treatment guidelines for ADHD. These guidelines reviewed studies by Ford et al. that found that 3.6 percent of boys and 0.85 percent of girls in Britain qualified for a diagnosis of ADHD using the American DSM-IV criteria. The guidelines go on to state that the prevalence drops to 1.5% when using the stricter criteria for the ICD-10 diagnosis of hyperkinetic disorder used mainly in Europe.

A systematic review of the literature in 2007 found that the worldwide prevalence of ADHD was 5.29 percent, and that there were no significant differences in prevalence rates between North America and Europe. The review did find differences between prevalence rates in North America and those in Africa and the Middle East, but cautioned that this may be due to the small number of studies available from those regions.

Norwegian National Broadcasting (NRK) broadcast a short television series in early 2005 on the increase in the use of Ritalin and Concerta for children. Sales were six times higher in 2004 than in 2002. The series included the announcement of a successful group therapy program for 127 unmedicated children aged four to eight, some with ADHD and some with oppositional defiant disorder.

Politics and media

North America

The validity of the work of many of the ADHD experts (including Biederman) has been called into question by Marcia Angell, former editor in chief of the New England Journal of Medicine, in her book review, "Drug Companies & Doctors: A Story of Corruption." Newspaper columnists such as Benedict Carey, science and medical writer for The New York Times, have also written controversial articles on ADHD.

In 1998, the US National Institutes of Health (NIH) released a consensus statement on the diagnosis and treatment of ADHD. The statement, while recognizing that stimulant treatment is controversial, supports the validity of the ADHD diagnosis and the efficacy of stimulant treatment. It found controversy only in the lack of sufficient data on long-term use of medications and in the need for more research in many areas.

In 2014, a preliminary retrospective analysis on the effect of increased use of methylphenidate among children in Quebec due to a policy change found little evidence of positive effects and limited evidence of negative effects.

United Kingdom

The National Institute for Health and Care Excellence (NICE) concluded that while it is important to acknowledge the body of academic literature which raises controversies and criticisms surrounding ADHD for the purpose of developing clinical guidelines, it is not possible to offer alternative methods of assessment (i.e. ICD 10 and DSM IV) or therapeutic treatment recommendations. NICE stated that this is because the current therapeutic treatment interventions and methods of diagnosis for ADHD are based on the dominant view of the academic literature. NICE further concluded that despite such criticism, ADHD represented a valid clinical condition, with genetic, environmental, neurobiological and demographic factors. The diagnosis has a high level of support from clinicians and medical authorities.

Baroness Susan Greenfield, a leading neuroscientist, wanted a wide-ranging inquiry in the House of Lords into the dramatic increase in the diagnosis of ADHD in the UK and its possible causes.

This followed a BBC Panorama programme in 2007, which highlighted US research (The Multimodal Treatment Study of Children with ADHD by the University of Buffalo showing treatment results of 600) suggesting drugs are no better than therapy for ADHD in the long-term. In the UK medication use is increasing dramatically. Other notable individuals have made controversial statements about ADHD. Terence Kealey, a clinical biochemist and vice-chancellor of University of Buckingham, has stated his belief that ADHD medication is used to control unruly boys and girls behavior.

The British Psychological Society said in a 1997 report that physicians and psychiatrists should not follow the American example of applying medical labels to such a wide variety of attention-related disorders: "The idea that children who don't attend or who don't sit still in school have a mental disorder is not entertained by most British clinicians." The National Institute for Health and Care Excellence (NICE), in collaboration with others, release guidelines for the diagnosis and treatment of ADHD. An update was last published in 2019.

Scientology

An article in the Los Angeles Times stated that "the uproar over Ritalin was triggered almost single-handedly by the Scientology movement." The Citizens Commission on Human Rights, an anti-psychiatry group formed by Scientologists in 1969, conducted a major campaign against Ritalin in the 1980s and lobbied Congress for an investigation of Ritalin. Scientology publications claimed the "real target of the campaign" as "the psychiatric profession itself" and said that the campaign "brought wide acceptance of the fact that (the commission) [sic] and the Scientologists are the ones effectively doing something about ... psychiatric drugging".

Other views

In the UK, Susan Greenfield spoke out publicly in 2007 in the House of Lords about the need for a wide-ranging inquiry into the dramatic increase in the diagnosis of ADHD, and possible causes. Her comments followed a BBC Panorama program that highlighted research that suggested medications are no better than other forms of therapy in the long term. In 2010, the BBC Trust criticized the 2007 Panorama program for summarizing the research as showing "no demonstrable improvement in children's behaviour after staying on ADHD medication for three years" when in actuality "the study found that medication did offer a significant improvement over time" although the long-term benefits of medication were found to be "no better than children who were treated with behavior therapy." In 2017, Senator Johnny Isakson was criticized by his constituents when he stated that ADD is not a learning disability but a "parental deficit disorder", and that it is a result of parents not "raising their kids like they should".