ADHD Is Now Widely Overdiagnosed and for Multiple Reasons
A 2017 meta-study spotlights the problem of overdiagnosis.
Posted October 20, 2017 | Reviewed by Lybi Ma
There are now clear signs that child and adolescent mental disorders are widely overdiagnosed, according to the authors of a large meta-study published earlier this year. The researchers, whose comprehensive results appear in Child and Adolescent Psychiatry and Mental Health, raise concern about the number of ADHD diagnoses across developed countries, and in the U.S. in particular.
Among the driving factors, the authors point to “very low” levels of agreement among diagnosticians (“interrater reliability”); ambiguously worded diagnostic criteria; excessive reliance on “heuristics” (a methodology involving educated guesswork and stereotyping); the “halo effect,” involving carry-over information from related but different diagnoses; and that just 1 in 4 pediatricians “reports relying on DSM criteria.”
Other factors seen as responsible and requiring greater caution include a well-established pattern of overdiagnosing ADHD in boys, based on a tendency among evaluators to “overrate male externalizing behavior,” and the relative age effect, where children born close to kindergarten or school cut-off dates are, one of the studies cited found, 30 to 60 percent more likely to be diagnosed with ADHD. They are also likely to “receive psychostimulants” such as Ritalin “twice as often as children born only a few days later, but after the cut-off date.”
Significantly, the relative age effect was shown to drive overdiagnosis not just in the U.S., but also in Canada, Sweden, Iceland, and the U.K. Extrapolated to the U.S. population as a whole, the consequences are stark: “Approximately 1.1 million children received an inappropriate diagnosis [of ADHD] and over 800,000 received stimulant medication due only to relative [im]maturity.”
After a systematic literature search using Medline, PsychINFO, PubMed, and Web of Science, tied on a sequence of relevant keywords, the authors—Eva Charlotte Merten, Jan Christopher Cwik, Jürgen Margraf, and Silvia Schneide—“found significant evidence of overdiagnosis of attention-deficit/hyperactivity disorder” in the U.S. and other developed countries, with notable signs “that diagnosticians are prone to making mistakes in the decision-making process,” resulting in both misdiagnosis and overdiagnosis.
One study bearing out these findings (Bruchmüller et al 2012) sent “case vignettes describing a child fulfilling or not fulfilling diagnostic criteria for ADHD to 473 child and adolescent psychotherapists and asked them to indicate which diagnosis they would assign.” Overall, “16.7 percent of psychotherapists diagnosed ADHD although diagnostic criteria were not fulfilled.” In addition, “only 7 percent gave no diagnosis,” although the altered case vignette did, in fact, fulfill the criteria for ADHD, at least according to the DSM. As a result, “there were significantly more false-positive than false-negative diagnoses.”
The same study found that ADHD was diagnosed “two times more often in the boy-version of the case vignettes,” reflecting a common finding in ADHD research that boys and male teens are far more likely than their female counterparts to receive a diagnosis. Here, too, “there is a difference between clinical data, with male to female ratios between 5:1 and 9:1, and epidemiological data with ratios of approximately 3:1.”
Another study whose findings are extrapolated (Wolraich et al 1990) determined that “only a quarter of pediatricians report relying on DSM criteria,” while 88 percent of the 457 patients screened—including, importantly, those who did not meet the criteria for ADHD—were treated with methylphenidate (Ritalin), an outcome pointing to clear signs of overprescribing, not least with prevalence rates running at roughly 1 in 5 among U.S. schoolchildren.
“The diagnostic criteria of ADHD also contain risks,” the authors of the meta-study indicate, “since they lack an exclusion criterion due to medical conditions,” such as sleep apnea, that can resemble ADHD. “Beside [such] evidence for low validity of diagnostic criteria, at least in the case of ADHD,” they add, “it is evident that diagnostic criteria are not reliable enough, as even trained clinicians interpret same symptoms differently.” That may be because the criteria listed in the DSM, when pediatricians do consult it, include behavioral characterizations as open-ended and overlapping as “fail[ing] to finish things,” has “difficulty sticking” to tasks, and “shifts excessively from one activity to another.”
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Finally, and no less significant, the researchers involved in the meta-study bring welcome attention to the problem of “intentional overdiagnosis due to health policy constraints.” This is especially acute in the U.S., where “in many health care systems a diagnosis is required in order to access and reimburse treatment.” In such scenarios, which the studies in question suggest may be widespread, “intentional wrong coding in diagnosing mental disorders does occur in child and adolescent mental health services and can partly account for the overdiagnosis found in studies reevaluating earlier diagnoses.”
When psychostimulants such as Ritalin and Adderall are added to the mix, as books such as Alan Schwarz’s ADHD Nation: Children, Doctors, Big Pharma, and the Making of an American Epidemic (2016) have well-documented, it is unsurprising that another European dissenter, French psychiatrist Patrick Landman, would characterize ADHD as a “bespoke” disorder, modeled to fit pre-existing chemical substances such as methylphenidate (Ritalin). Landman, who has voiced extensive criticism of DSM diagnoses and procedures and guest-written for this blog, calls ADHD “a pharmaco-induced pseudo-disease now completely out of control.”
“In itself,” he observes, pharmaco-induction—“nosography … modified by pharmacology”—“is not particularly shocking. We have seen it, for example, in the transformation of anxiety disorders into two distinct categories, which respond to either antidepressants (panic disorders) or anxiolytics (Generalized Anxiety Disorder). However, in the case of ADHD, we are speaking about a psychostimulant, a type of amphetamine, that is being administered to children [in ever-increasing numbers, per the meta-study] … with methylphenidate becoming a kind of academic doping, an ‘opium of the school people.’”
Corroborating Landman’s point, the sharp rise in Ritalin prescriptions directly parallels ADHD’s dramatic ascent in diagnostic rates, with Ritalin prescriptions, in Schwarz’s reporting, “doubling every six years since the early 1970s” and in the late 1990s increasing “a stupefying 400 percent in just five years,” with just a brief falling-off period between 1987 and 1990. That was due to several well-publicized lawsuits and media coverage warning of lax prescribing. “From just 1990 to 1993,” Schwarz continues, “annual diagnoses more than doubled from 900,000 to 2 million. They kept rising from there.”
“With each new edition of the DSM, Landman notes, “the diagnostic restrictions have been loosened,” making it possible to “expand the drug’s market” rapidly. In addition, with the moniker Adderall echoing the phrase “ADD for All,” ADHD has become “an all-encompassing diagnosis which has many confounding factors: it can be given to epileptic children, traumatized children, children who have trouble sleeping, immature children, highly gifted children, psychotic children, autists, children with learning difficulties (dyslexia, dysgraphia, etc.), children with sensorial disorders, children showing obsessional and anxiety symptoms, Tourette’s syndrome, schizophrenia, mood disorders, and so on.”
“No other disorder listed in DSM-5 contains so many confounding factors,” he adds, and in the latest version of the DSM, in particular, “ADHD is no longer listed as a behavioral disorder, but is instead included among the neurodevelopmental disorders,” altering its perceived determinants and remedies as neuroscientific and biomedical, respectively, when “ADHD is sadly often a medical veil concealing different psychological, academic, pedagogical and social problems.”
In ways that reinforce the findings of the German meta-study on ADHD prevalence rates, false positives, and widespread overdiagnosis, especially in the U.S., Landman argues that “we should de-medicalize the difficulties of paying attention at school whenever necessary and instead support pedagogical innovations” such as limiting screen time, increasing rec time at schools, and supporting healthier, less sugar- and caffeine-intensive diets, given the quantities ingested. Not only would such interventions help “reduce the rates of ADHD”; they would also narrow the risk—if it’s not too late—that skyrocketing diagnostic trends involving the medication of millions of American schoolchildren don’t become the model and rule for all developed nations.
Bruchmüller, K., Margraf, J., and Schneider, S. “Is ADHD diagnosed in accord with diagnostic criteria? Overdiagnosis and influence of client gender on diagnosis” (2012). J Consult Clin Psychol. 80:1. [Link]
Landman, P. “Why should we contest ADHD?” (10.10.2017). Stop DSM. [Link]
Merten, E. C., Cwik, J. C., Margraf, J., and Schneider, S. (2017). “Overdiagnosis of mental disorders in children and adolescents (in developed countries).” Child and Adolescent Psychiatry and Mental Health 11:1. [Link]
Schwarz, A. ADHD Nation: Children, Doctors, Big Pharma, and the Making of an American Epidemic (2016). Scribner. [Link]
Wolraich, M. L., Lindgren, S., and Stromquist, A., et al (1990). “Stimulant medication use by primary care physicians in the treatment of attention deficit hyperactivity disorder.” Pediatrics 86:1. [Link]