St. John's wort for the treatment of psychiatric disorders.

St. John's wort (Hypericum perforatum) has been extensively studied and reviewed for its use in depression; however, there is less salient discussion on its clinical application for a range of other psychiatric disorders. This article outlines the current evidence of the efficacy of St John's wort in common psychiatric disorders, including major depression, bipolar depression, attention-deficit hyperactivity disorder, obsessive-compulsive disorder, social phobia, and somatization disorder. Mechanisms of action, including emerging pharmacogenetic data, safety, and clinical considerations are also detailed.