Attention deficit hyperactivity disorder controversies

Frequently observed differences in the brain between ADHD and non-ADHD patients have been discovered,[7] 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, between individuals with and without ADHD.[8]

ADHD is said to be highly heritable: twin studies suggest that genetics explain 70-80% in the variation of ADHD.[9] 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.[10] It has also been argued that ADHD is a heterogeneous disorder[11] 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."[12] 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.[13]

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.[14] 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".

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.[15] 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.[16] The current way that diagnosis are made is using the DSM-5, along with a possible physical and visual examination.[17]

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)."[18] 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.[19]

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.[20]

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.[21]

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.[22]

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.[20] 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.[22] Learning disorders are found in 20% to 40% of children with ADHD.[20]

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.[23]

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%.[24] However, as little as 11% of these adults with ADHD actually receive assessment, and furthermore, any form of treatment.[25] 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.[26]

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.[20] This difference in gender can be explained, for the majority, by the different ways boys and girls express symptoms of this particular disorder.[27] Typically, females with ADHD exhibit less disruptive behaviors and more internalizing behaviors.[18][28] 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.[27] The current diagnostic criteria appear to be more geared towards males than females, and the ADHD characteristics of men have been over-represented.[29] 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.[28]

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.[18]

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.[30]

The National Institute of Mental Health recommends stimulants for the treatment of ADHD, and states that, "under medical supervision, stimulant medications are considered safe".[35] A 2007 drug class review found no evidence of any differences in efficacy or side effects in the stimulants commonly prescribed.[36]

Between 1993 and 2003 the worldwide use of medications that treat ADHD increased almost threefold.[37] Most ADHD medications are prescribed in the United States.[37] 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.[38] 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.[38] 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.[39] They assert that in the early 2000s amphetamine use was "widespread in Europe."[39]

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.[40] 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 numerous use of Adderall prescription have increased from 1.3 million in 1996 to nearly 6 million in 1999.[41]

Some parents and professionals have raised questions about the side effects of drugs and their long-term use.[42] 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.[43][44][45]

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.[46] 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.[47][48][49][50]

The effects of amphetamine and methylphenidate on gene regulation are both dose- and route-dependent.[51] Most of the research on gene regulation and addiction is based upon animal studies with intravenous amphetamine administration at very high doses.[51] 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.[51] 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.[52][53]

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.[54][55][56] The average reduction in final adult height from continuous stimulant therapy over a 3-year period is 2 cm.[56]

Reviews of clinical stimulant research have established the safety and effectiveness of long-term amphetamine use for ADHD.[57][58][59] 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.[54] During treatment, the children experienced improvements in attention, disruptive behaviors, and hyperactivity, and an average change of +4.5 in IQ.[54] 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 less associated disorders could find greater functional improvements.[54]

A 2008 review found that the use of stimulants improved teachers' and parents' ratings of behavior; however, it did not improve academic achievement.[60] The same review also indicates growth retardation for children consistently medicated over three years, compared to unmedicated children in the study.[60] Intensive treatment for 14 months has no effect on long-term outcomes 8 years later.[61] No significant differences between the various drugs in terms of efficacy or side effects have been found.[62][63]

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.[64][65] 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.[64] 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.[64]

Research has shown that adherence and acceptability improvements are possible with accessible and convenient community-based treatment options.[66] 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.[67]

Stimulants used to treat ADHD are classified as Schedule II controlled substances in the United States.[68]

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.[69]

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.[70]

Stimulant medications may be resold by patients as recreational drugs, and methylphenidate (Ritalin) is used as a study aid by some students without ADHD.[71]

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%.[72] 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.[70]

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.[73]

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.[85] 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.[86] 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.[87]

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.[88]

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.[89]

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,[90] in her book review, "Drug Companies & Doctors: A Story of Corruption."[91] Newspaper columnists such as Benedict Carey, science and medical writer for The New York Times, have also written controversial articles on ADHD.[92][93]

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.[94]

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.[95]

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.[85]^:p.133 NICE further concluded that despite such criticism, ADHD represented a valid clinical condition,[85]^:p.138 with genetic, environmental, neurobiological and demographic factors.[85]^:p.139 The diagnosis has a high level of support from clinicians and medical authorities.[85][96]

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.[97] 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.[97][98] 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.[99]

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."[100][101] The National Institute for Health and Care Excellence (NICE), in collaboration with others, release guidelines for the diagnosis and treatment of ADHD.[102] An update was last published in 2019.[103]

An article in the Los Angeles Times stated that "the uproar over Ritalin was triggered almost single-handedly by the Scientology movement."[104] 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.[104] 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".[104]

Tom Cruise has described the medications Ritalin (methylphenidate) and Adderall (a mixed-salt amphetamine formulation) as being used as "street drugs".[105] Ushma S. Neill criticized this view, stating that the doses of stimulants used in the treatment of ADHD do not cause addiction and that there is some evidence of a reduced risk of later substance addiction in children treated with stimulants.[106]

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.[107] 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."[108] 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".[109]