In this double-blind, placebo-controlled 10-week trial, the anxiolytic properties of the nonbenzodiazepine buspirone were compared with the benzodiazepine lorazepam and placebo in 125 outpatients with generalized anxiety disorder according to DSM-III. After a 3- to 7-day wash-out period, patients were allocated at random to receive orally 3 x 5 mg buspirone (n=58), 3 x 1 mg lorazepam (n=57), or placebo (n=10) over a 4-week period. The study also comprised a 2-week taper period and a 4-week placebo-control period to assess the stability of clinical improvement. The patient's clinical state was estimated on entry and at weekly intervals by general practitioners using the Hamilton Rating Scale for Anxiety (HAM-A) and Clinical Global Impression (CGI) assessment and by a self-rating scale (State Trait Anxiety Inventory X2=STAI-X2). Lorazepam treatment resulted in descriptively, but not significantly, greater improvement on the Hamilton Rating Scale for Anxiety during the whole treatment (week 0-4) and taper period (week 5, 6) than did buspirone. After treatment with active drugs had been discontinued, the 4-week placebo control period showed buspirone-treated patients to display a stability of clinical improvement, while the symptoms of lorazepam-treated patients worsened at week 7-10. Both buspirone and lorazepam were more efficacious in reducing anxiety symptoms than placebo during the treatment and taper period; however, in contrast to the active drugs (buspirone, lorazepam), patients of the placebo group showed further clinical improvement during the control period, especially in the HAM-A score, so differences between placebo and active drugs became smaller at the end of the study.