Trends in office-based treatment of adults with stimulants in the United States

Abstract

Objective: The authors investigated trends and patterns in stimulant treatment of adults visiting office-based medical practices in the United States.

Method: A time series analysis of data from the 1994 to 2009 National Ambulatory Medical Care Surveys (no. of visits = 372,702) was performed, focusing on adult (aged ≥ 18 years) visits in which stimulant medications (amphetamine salts, methylphenidate, or pemoline) were prescribed. The authors computed trends in the percentage of visits in which a stimulant was prescribed stratified by background and clinical patient characteristics. Results are reported as odds ratios (ORs) over the 1994 to 2009 period. The authors also compare visits to psychiatrists and nonpsychiatrist physicians that yielded a stimulant prescription to an adult.

Results: The percentage of visits in which stimulants were prescribed increased from 0.11% (1994-1997) to 0.70% (2006-2009) (OR = 13.72, 95% confidence interval [CI], 9.40-20.03). Among adults aged 18 to 29 years, the corresponding increase in stimulant visits was from 0.17% to 1.83% (OR = 30.14, 95% CI, 15.84-57.36). Stimulant prescriptions increased significantly more rapidly among visits without a clinical ADHD diagnosis (OR = 11.86, 95% CI, 7.49-18.80) than among visits with such a diagnosis (OR = 5.45, 95% CI, 2.96-10.04) (interaction P = .04) and among visits to nonpsychiatrist physicians (OR = 21.54, 95% CI, 12.84-36.12) than psychiatrists (OR = 10.64, 95% CI, 6.72-16.86) (interaction P = .03). By 2006-2009, nonpsychiatrist physicians provided most (57.7%) of the stimulant prescriptions linked to adult office-based visits. As compared with psychiatrists, nonpsychiatrist physicians diagnosed ADHD in a significantly smaller proportion of their adult visits in which stimulants were prescribed (62.5% vs 34.4%, P < .0001).

Conclusions: Between 1994 and 2009, there was a substantial increase in stimulant prescriptions during adult outpatient visits, especially during visits of younger adults. The increase in stimulant treatment occurred significantly more rapidly in the practices of nonpsychiatrist physicians than in those of psychiatrists.