Background: Certain medications may contribute to the etiology of depressive symptoms and disorders. Research in this area, however, has been hampered by methodological and conceptual problems. This review had two objectives: to identify evidence linking medical drugs to depressive symptoms and disorders, and to summarize this evidence in a clinically meaningful way. Methods: Electronic literature searches were performed and studies were reviewed with reference to critical methodological features. Results: No medications causing the typical major depressive syndrome were identified. Evidence was found linking corticosteroids, interferon-α, interleukin-2, gonadotropin-releasing hormone agonists, mefloquine, progestin-releasing implanted contraceptives and propranolol to the etiology of atypical depressive syndromes. Conclusions: A small number of drugs have been shown capable of inducing depressive symptoms. Drug-induced depression appears to differ symptomatically from classical major depression.