A multicenter study indicates that trazodone appears to be effective in treating endogenous depression and to have significant advantages over the tricyclic antidepressant, imipramine, in terms of side effects, especially unwanted anticholinergic effects. Trazodone may also have a special therapeutic potential in the elderly, in schizophrenics with secondary depression, and possibly in the treatment and prophylaxis of depression in bipolar affective disorders not fully controlled by lithium.