Clearly, not every person who meets criteria for ADHD is in need of a medication intervention. A discrepancy between ADHD prevalence and rates of stimulant prescriptions does not automatically prove that medications are underprescribed in the population. Nor do data support a conclusion that an epidemic of ADHD med-ication overprescribing is occurring.
Stimulant prescription rates are complex and vary by geographic location, age, and gender.14 Studies have found overprescribing in some regions of the United States and underprescribing in others. As reported by the CDC in 2003, ADHD prevalence ranged from a low of 5.0% in Colorado to a high of 11.1% in Alabama. Rates of medication treatment for ADHD ranged from 40.6% of patients in California to 68.5% in Nebraska.14 These data do not sug-gest a pattern of overprescribing of stimulants. However, in an 11-county epidemiological study of mental health status among children in western North Carolina, Angold and colleagues15 found that 7.3% of children were receiving stimulants but only 3.4% of children met an unequivocal diagnosis of ADHD, which suggests that pockets of overprescribing do exist.
In addition, stimulant prescription rates vary by sex and age. ADHD diagnostic rates and stimulant treatment rates are higher in boys than in girls younger than 20 years.9 Rates of stimulant treatment are highest among boys aged 12 years and girls aged 11 years, and they decline with age.14 The National Survey of Children’s Health showed that the factors associated with medication treatment for ADHD included younger age, the burden of impairment from symptoms, and a recent health care contact.5 Some factors associated with possible ADHD misdiagnosis and stimulant misprescribing are listed in Table 1.
Simple pronouncements of the overmedication of youth with ADHD based on temporal trends in the absolute rate of rise of stimulant quota production and stimulant prescriptions cannot be supported. The majority of the literature published to date does not support the general idea that ADHD is overdiagnosed nor does it support the idea that stimulants are overprescribed in children and adolescents in the United States. However, the data also suggest that there continue to be geographic areas of stimulant overprescribing or inappropriate prescribing.
What is already known about overdiagnosis and overprescribing in ADHD?
■ ADHD is the most extensively studied pediatric mental health disorder, yet controversy and public debate over the diagnosis and medication treatment of the disorder continue. Questions and concerns continue to be raised by professionals, media commentators, and the public about the possibility that ADHD is overdiagnosed in youths and that stimulants are overprescribed.
What new information does this article provide?
■ This article reviews what is known about the prevalence of ADHD and stimulant prescribing rates in children and adolescents in the United States. While the data do not suggest a general problem with ADHD overdiagnosis and stimulant overprescribing, there continues to be variability in diagnosis and prescribing rates. Reasons for the continued controversy include fears of stimulant abuse and diversion, physician overprescribing, limited managed care carve-out payer resources to support evidence-based standards of ADHD evaluation and treatment, and continuing unease as to the legitimacy of the ADHD diagnosis.
What are the implications for psychiatric practice?
■ Comprehensive physician ADHD evaluation practices are essential for accomplishing evidence-based stimulant prescribing and for reducing unwanted variation in stimulant prescribing rates. This, in turn, should help reassure the public that management is accomplished consistently and with due expertise.
Stimulant abuse and diversion
Despite more than 250 randomized controlled medication trials attesting to the efficacy and safety of stimulant use in patients with ADHD, there continues to be controversy, especially regarding abuse and diversion. It is important to distinguish between these issues. Stimulant abuse refers to the continued use of a drug that leads to significant impairment in daily functioning characterized by recurrent use under hazardous conditions, such as while driving an automobile or operating machinery, and by legal and interpersonal problems.16 Diversion is the practice by which legitimate stimulant prescriptions for ADHD are diverted for reasons other than treating ADHD.17
Methylphenidate and amphetamine used to treat the core ADHD symptoms of inattention, impulsivity, and hyperactivity have an established potential for abuse. Preclinical and clinical studies show that both types of stimulants have reinforcing effects that are similar to each other and to drugs of abuse, such as cocaine.16,18 Findings from a study by Biederman and colleagues19 indicate that a diagnosis of ADHD increases the risk of early-onset substance use disorders that have an aggressive course. These data suggest a potential relationship between ADHD, stimulant treatment, and later substance use disorders.
However, despite the established abuse potential of stimulants, the evidence that methylphenidate(Drug information on methylphenidate) and amphetamine are readily abused in the ADHD population in the formulations and doses used clinically is limited.16 Rather than abusing stimulants, patients with ADHD frequently take less medication than prescribed.20 The reinforcing effects of stimulants in ADHD patients may be associated more with clinical efficacy than with abuse liability.