Background: St. John's wort, the popular herbal remedy touted as an antidepressant, is generally thought to be benign, with few reported side effects. Given its possible efficacy as an antidepressant, evaluation of its propensity to cause affective switching should be evaluated.
Methods: This report presents two cases of mania temporally associated with the use of St. John's wort (hypericum).
Results: As with other antidepressant agents, St. John's wort may precipitate hypomania, mania, or an increased cycling of mood states, particularly in patients with occult bipolar disorder.
Conclusions: Because the majority of people who take this popular over-the-counter preparation do so without formal psychiatric evaluations, risk of hypericum-induced mania may be significant. Physicians should screen patients for a history of hypomania or mania before recommending use of St. John's wort for depression.