We performed a randomized, double-blind clinical trial comparing the efficacy and safety of zimelidine with amitriptyline and placebo in outpatients with major depression, in particular patients with mixed anxiety/depressive symptomatology. Overall, amitriptyline was more effective than zimelidine and placebo after 4 weeks of treatment. However, when those patients with more severe depression were specifically examined, both antidepressants were equal in efficacy and superior to placebo. We also found no evidence for a greater likelihood of a zimelidine-induced peripheral neuropathy in this study. The present results suggest that zimelidine may be more effective in the treatment of severely depressed patients, rather than those with more mild mixed anxiety/depressive syndromes.