A controlled study of trazodone, imipramine, and placebo in outpatients with endogenous depression.

A 4-wk double-blind controlled study of the antidepressant efficacy of the triazolopyridine derivative trazodone, in contrast to imipramine and placebo, was carried out in 30 endogenously depressed outpatients. Trazodone was found to be equivalent in efficacy to imipramine and statistically significantly superior to placebo. Trazodone showed a significant antidepressant effect relative to placebo when outcome was measured after only 7 days of treatment. This antidepressant effect was sustained for at least 5 mo as indicated by an open study phase following the double-bind study. Side effects, particularly anticholinergic properties, were significantly less apparent on trazodone compared to imipramine. A limited study of the relationship of trazodone plasma levels to therapeutic outcome revealed no simple linear relationship and represents a direction for future research.