We report the findings of a randomized, double-blind, placebo-controlled, parallel, generalized anxiety disorder (GAD) outpatient study. The purpose of the study was to compare the efficacy, safety, and tolerability of ipsapirone, an azapirone and 5-HT1A agonist, given at a total daily dose of 10 mg to 30 mg, with a total daily dose of 2 mg to 6 mg of lorazepam or placebo in 90 outpatients with GAD of moderate or greater severity. At baseline, all patients had a Hamilton Anxiety Scale (HAM-A) score of > or = 18 and Covi anxiety score of > or = 8. After a 1-week single-blind washout, patients entered a 4-week double-blind period with an optional extension for another 4 weeks, followed by a 2-week single-blind placebo washout. Ipsapirone and lorazepam ratings on the HAM-A and Clinical Global Impressions (CGI) were significantly (p < .05) superior to placebo at the end of the acute and maintenance periods of the trial, with a 50 percent HAM-A reduction on active drugs vs. 20 percent on placebo. The anxiety of patients receiving lorazepam, but not ipsapirone, rebounded during the final placebo washout.