A double-blind, placebo-controlled, randomized trial was carried out to compare the efficacy and tolerability of paroxetine in outpatients with moderate to moderately severe depression without mania. Paroxetine was found to be an effective antidepressant drug when compared to placebo. For most of the measures of efficacy the benefit appeared after two weeks of therapy, but sleep was improved after one week. Patients taking paroxetine complained of more adverse effects than those on placebo; they were mainly gastrointestinal with nausea the most commonly reported.