To evaluate whether the trend in adults seeking medical care for the treatment of attention deficit/hyperactivity disorder (ADHD) reflects the upward pattern seen among children.

Data from the United States (U.S.) National Ambulatory Medical Care Survey (NAMCS) were utilized for this analysis. The NAMCS is an ongoing annual survey of a representative sample of U.S. office-based physician practices. The number and rate of office-based physician visits resulting in a diagnosis of ADHD (International Classification of Diseases, 9th Revision, Clinical Modification code 314.00 or 314.01) among patients age 20 years or older, were discerned for the years 1995 through 2004. Trend analysis was conducted using five time intervals: 1995-96; 1997-98; 1999-00; 2001-02; 2003-04.

Over the time-frame, national estimates of the number of annualized office-based physician visits documenting a diagnosis of ADHD among adults increased 4.7-fold; from 582,728 in 1995-96, to 2,738,285 in 2003-04 (p < 0.05). Adjusted for population growth, the rate per year of office visits per 1,000 U.S. population ≥$20 years old resulting in a diagnosis of ADHD more than quadrupled; increasing from 3.1 per 1,000 in 1995-96, to 13.0 in 2003-04. The majority of office visits documented a prescription for stimulant pharmacotherapy or atomoxetine (available since late 2002), increasing from 61.7% in 1995-96, to 77.8% in 2003-04.

As with children, the rate of adults seeking medical care for ADHD has increased significantly. By 2003-04, adults accounted for more than 1 in 4 (28.8%) office visits resulting in a diagnosis of ADHD.