Trends in ADHD diagnosis and stimulant treatment
ADHD is a psychiatric disorder with a long history. It was first described by the English pediatrician Sir George Frederick Still in 1902, and initial diagnostic classifications emphasized the symptoms of hyperactivity and impulsivity. The diagnostic terms used to describe children with this disorder changed frequently in the 20th century. With the introduction of DSM-III in 1980, the symptom of inattention gained ascendancy and the condition was officially listed as attention-deficit disorder. DSM-IV contains the diagnosis of ADHD with 3 subtypes: combined, inattentive, and hyperactive-impulsive. Further modifications of the criteria for the disorder are expected when DSM-5 is introduced.
Before 1970, the diagnosis of ADHD was relatively rare for schoolchildren and almost nonexistent for adolescents and adults. Between 1980 and 2007, there was an almost 8-fold increase of ADHD prevalence in the United States compared with rates of 40 years ago. Considering the prevalence of school-administered stimulants as synonymous with the prevalence of ADHD, Safer and colleagues3,4 estimated the prevalence of ADHD in American schoolchildren as 1% in the 1970s, 3% to 5% in the 1980s, and 4% to 5% in the mid to late 1990s. In 2007, using data from the National Survey of Children’s Health, Visser and colleagues5 reported that 7.8% of youths aged 4 to 17 years had a diagnosis of ADHD and 4.3% reported current use of a medication for the disorder.
The rise in prevalence stemmed from a complex confluence of forces and events that came together in the first half of the 1990s and permitted a dramatic expansion of ADHD diagnosis and treatment.6 The growing political strength of children’s welfare advocates and the mental health consumer’s movement associated with decreasing stigma resulted in changes to federally funded special education programs. The Individuals with Disabilities Education Act recognized ADHD as a disability, and children with ADHD became eligible for school accommodations.
Beginning in the 1990s, Congress expanded eligibility criteria for Medicaid, especially for children. This fueled a rapid increase in coverage for psychotropic medications, including stimulants.6 At the same time, scientific knowledge about the longitudinal course of ADHD and its lifetime morbidity, heritability, and neurobiology was rapidly increasing, This provided empiric evidence as well as a scientific and neurobiological rationale for medication intervention.7,8 Also, the managed care psychiatric carve-out health insurance industry sought to rein in the costs associated with psychiatric illness and supported pharmacological interventions for complex psychiatric disorders, including pediatric disorders.
In 1997, Congress passed the FDA Modernization Act, which encouraged the pharmaceutical industry to develop and test drugs for children by extending patent exclusivity. This resulted in a dramatic increase in randomized controlled trials in children that involved stimulant compounds for ADHD and further supported an evidence-based rationale for medication intervention in ADHD. As a result, the prescribing of stimulants for children with ADHD increased 4-fold between 1987 and 1996, with a further increase of 9.5% between 2000 and 2005. Currently, slightly more than 4% of children and adolescents in the United States use ADHD medications.5,9
Doubt and confusion as to where this disorder fits into the general spectrum of illness further feeds the general perception that ADHD is a socially constructed disorder rather than a valid neurobiological disorder.
The rise in stimulant prescribing for youths must be taken in context. Between 1990 and 2005 there was a rapid rise in pediatric prescriptions for many psychiatric medications—not only stimulants. There was a 5-fold increase for antipsychotics between 1993 and 2002, and a 3-fold increase for antidepressants between 1997 and 2002.10,11 Thus, the rise in stimulant prescribing for pediatric ADHD was only part of a larger shift to an emphasis on medication interventions for the treatment of children with early-onset and complex behavioral and mental health disorders.
Public perception of stimulant overprescribing is driven by concerns over the rapid rise in the amount of available stimulants produced in the United States over the past 3 decades. For sale stimulant production quotas are published yearly by the Drug Enforcement Administration.12 The rapid rise in the production quota of for-sale methylphenidate(Drug information on methylphenidate) (excluding amphetamine) is seen in the Figure. With the production of more stimulants every year, worries about the increased availability of stimulants for abuse and diversion rise as well. Rising production rates are cited as proof of stimulant overprescribing by physicians and indirect evidence of the overdiagnosis of ADHD among children.2
The extant scientific research suggests a much more complicated and nuanced picture of stimulant prescribing. Comparisons of the prevalence of ADHD among youths aged 4 to 17 years (7.8%) with stimulant prescription rates of between 4.3% and 4.4% do not support the idea of a culture of permissive stimulant overprescribing.5,9 Moreover, recent data from the National Health and Nutrition Examination Survey, a nationally representative probability sample of 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.13
