A national survey of psychotherapeutic drug use was carried out in the U.S.A. in 1979. Data were obtained from a probability sample (n = 3161) of adults in the general population, using a clinically-oriented interview lasting an average of 90 minutes. The data provide estimates of the prevalence of using anxiolytic and other psychotherapeutic medications. Among users they also provide detailed descriptions of patterns of use and characteristics associated with various patterns of use. The study found that 11% of American adults used an anxiolytic during the 12 months prior to the survey. Benzodiazepines accounted for 84% of the anxiolytics mentioned. The analyses compared (i) users of anxiolytics with non-users and (ii) three groups of anxiolytic users classified according to pattern (frequency and regularity) of use. The results were generally consistent with an illness treatment model of psychotherapeutic drug use, and they raise interesting questions about short-term single-occasion use.