Paroxetine, a phenylpiperidine derivative, is an antidepressant that selectively inhibits serotonin reuptake. In this study 111 outpatients with major depression diagnosed by DSM-III criteria were treated with either paroxetine or placebo in a 6-week, randomized, double-blind study. Paroxetine was significantly superior to placebo on six of the seven major efficacy variables. Significant differences in favor of paroxetine were apparent by Week 2. Paroxetine was also well tolerated. These results support the efficacy and safety of paroxetine as a treatment for patients with major depression.