A German children's book from 1845 by Heinrich Hoffman featured “Fidgety Philip,” a boy who was so restless he would writhe and tilt wildly in his chair at the dinner table. Once, using the tablecloth as an anchor, he dragged all the dishes onto the floor. Yet it was not until 1902 that a British pediatrician, George Frederic Still, described what we now recognize as attention-deficit hyperactivity disorder (ADHD). Since Still's day, the disorder has gone by a host of names, including organic drivenness, hyperkinetic syndrome, attention-deficit disorder and now ADHD.

Despite this lengthy history, the diagnosis and treatment of ADHD in today's children could hardly be more controversial. On his television show in 2004, Phil McGraw (“Dr. Phil”) opined that ADHD is “so overdiagnosed,” and a survey in 2005 by psychologists Jill Norvilitis of the University at Buffalo, S.U.N.Y., and Ping Fang of Capitol Normal University in Beijing revealed that in the U.S., 82 percent of teachers and 68 percent of undergraduates agreed that “ADHD is overdiagnosed today.” According to many critics, such overdiagnosis raises the specter of medicalizing largely normal behavior and relying too heavily on pills rather than skills—such as teaching children better ways of coping with stress.

Yet although data point to at least some overdiagnosis, at least in boys, the extent of this problem is unclear. In fact, the evidence, with notable exceptions, appears to be stronger for the undertreatment than overtreatment of ADHD.

Medicalizing Normality

The American Psychiatric Association's diagnostic manual of the past 19 years, the DSM-IV, outlines three sets of indicators for ADHD: inattention (a child is easily distracted), hyperactivity (he or she may fidget a lot, for example), and impulsivity (the child may blurt out answers too quickly). A child must display at least six of the nine listed symptoms for at least half a year across these categories. In addition, at least some problems must be present before the age of seven and produce impairment in at least two different settings, such as school or home. Studies suggest that about 5 percent of school-age children have ADHD; the disorder is diagnosed in about three times as many boys as girls.

Many scholars have alleged that ADHD is massively overdiagnosed, reflecting a “medicalization” of largely normative childhood difficulties, such as jitteriness, boredom and impatience. Nevertheless, it makes little sense to refer to the overdiagnosis of ADHD unless there is an objective cutoff score for its presence. Data suggest, however, that a bright dividing line does not exist. In a study published in 2011 psychologists David Marcus, now at Washington State University, and Tammy Barry of the University of Southern Mississippi measured ADHD symptoms in a large sample of third graders. Their analyses demonstrated that ADHD differs in degree, not in kind, from normality.

Yet many well-recognized medical conditions, such as hypertension and type 2 diabetes, are also extremes on a continuum that stretches across the population. Hence, the more relevant question is whether doctors are routinely diagnosing kids with ADHD who do not meet the levels of symptoms specified by the DSM-IV.

Some studies hint that such misdiagnosis does occur, although its magnitude is unclear. In 1993 Albert Cotugno, a practicing psychologist in Massachusetts, reported that only 22 percent of 92 children referred to an ADHD clinic actually met criteria for ADHD following an evaluation, indicating that many children referred for treatment do not have the disorder as formally defined. Nevertheless, these results are not conclusive, because it is unknown how many of the youth received an official diagnosis, and the sample came from only one clinic.

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Clearer, but less dramatic, evidence for overdiagnosis comes from a 2012 study in which psychologist Katrin Bruchmüller of the University of Basel and her colleagues found that when given hypothetical vignettes of children who fell short of the DSM-IV diagnosis, about 17 percent of the 1,000 mental health professionals surveyed mistakenly diagnosed the kids with ADHD. These errors were especially frequent for boys, perhaps because boys more often fit clinicians' stereotypes of ADHD children. (In contrast, some researchers conjecture that ADHD is underdiagnosed in girls, who often have subtler symptoms, such as daydreaming and spaciness.)

Pill Pushers?

Published reports of using stimulants for ADHD date to 1938. But in 1944 chemist Leandro Panizzon, working for Ciba, the predecessor of Novartis, synthesized a stimulant drug that he named in honor of his wife, Marguerite, whose nickname was Rita. Ritalin (methylphenidate) and other stimulants, such as Adderall, Concerta and Vyvanse, are now standard treatments; Strattera, a nonstimulant, is also widely used. About 80 percent of children diagnosed with ADHD display improvements in attention and impulse control while on the drugs but not after their effects wear off. Still, stimulants sometimes have side effects, such as insomnia, mild weight loss and a slight stunting of height. Behavioral treatments, which reward children for remaining seated, maintaining attention or engaging in other appropriate activities, are also effective in many cases.

Many media sources report that stimulants have been widely prescribed for children without ADHD. As Dutch pharmacologist Willemijn Meijer of PHARMO Institute in Utrecht and his colleagues observed in a 2009 review, stimulant prescriptions for children in the U.S. rose from 2.8 to 4.4 percent between 2000 and 2005. Yet most data suggest that ADHD is undertreated, at least if one assumes that children with this diagnosis should receive stimulants. Psychiatrist Peter Jensen, then at Columbia University, noted in a 2000 article that data from the mid-1990s demonstrated that although about three million children in the U.S. met criteria for ADHD, only two million received a stimulant prescription from a doctor.

The perception that stimulants are overprescribed and overused probably has a kernel of truth, however. Data collected in 1999 by psychologist Gretchen LeFever, then at Eastern Virginia Medical School, point to geographical pockets of overprescription. In southern Virginia, 8 to 10 percent of children in the second through fifth grades received stimulant treatment compared with the 5 percent of children in that region who would be expected to meet criteria for ADHD. Moreover, increasing numbers of individuals with few or no attentional problems—such as college students trying to stay awake and alert to study—are using stimulants, according to ongoing studies. Although the long-term harms of such stimulants among students are unclear, they carry a risk of addiction.

A Peek at the Future

The new edition of the diagnostic manual, DSM-5 (due out in May), is expected to specify a lower proportion of total symptoms for an ADHD diagnosis than its predecessor and to increase the age of onset to 12 years. In a commentary in 2012 psychologist Laura Batstra of the University of Groningen in the Netherlands and psychiatrist Allen Frances of Duke University expressed concerns that these modifications will result in erroneous increases in ADHD diagnoses. Whether or not their forecast is correct, this next chapter of ADHD diagnosis will almost surely usher in a new flurry of controversy regarding the classification and treatment of the disorder.