To use a single national data source to discern trends in the prevalence of office-based visits resulting in a diagnosis of attention deficit/hyperactivity disorder (ADHD) among girls, and trends in the prescribing of stimulant pharmacotherapy for its treatment in the United States (U.S.).

Data from the U.S. National Ambulatory Medical Care Survey were utilized for this analysis. The number and rate of office-based physician visits resulting in a diagnosis of ADHD (ICD-9-CM code 314.00 or 314.01) were discerned for the years 1991 through 2004, for children and adolescents aged 5 through 18 years. Gender-specific trend analyses were conducted using seven two-year time intervals.

Overall, the annualized number of office-based visits documenting a diagnosis of ADHD increased from 1,302,632 in 1991-92, to 6,513,479 in 2003-04. The annualized mean number of office-based visits documenting a diagnosis of ADHD among girls increased five-fold between 1991-92, and 2003-04 (from 296,389 to 1,473,854). The U.S. population-adjusted rate of office visits documenting a diagnosis of ADHD among girls increased 4.3-fold (from 12.3 per 1,000 girls to 52.6). Documentation of a diagnosis of ADHD and the prescribing of stimulant pharmacotherapy increased 4.2-fold for girls, from 7.5 per 1,000 girls in 1991-92, to 31.4 in 2003-04.

Although the number and rate of office-based visits among boys documenting a diagnosis of ADHD still far exceeds that of girls (3.4:1), the magnitude of the increase was as great among girls as boys during this time period, and contributed significantly to the overall upward trend.