Paroxetine is an investigational antidepressant that acts through selective inhibition of serotonin reuptake at the synapse. In this study, 81 outpatients with major depression according to 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 all major efficacy variables, including depression as well as anxiety, cognitive disturbance, insomnia, psychomotor retardation, and sleep disturbance. Significant differences in favor of paroxetine were apparent by Week 2. Paroxetine was also well tolerated. The results support the efficacy and safety of paroxetine as a treatment for patients with major depression.