Can I safely use St. John's wort if I have bipolar disorder?

If you have bipolar disorder, do not take St. John's wort without talking to your doctor. It may induce mania (excessive physical activity and impulsive behavior), and like other antidepressants, it may also accelerate your usual cycling between depression and mania. There have been cases in which mania developed after two to eight weeks of treatment with St. John's wort. The mania was relieved when the dose of St. John's wort was decreased and the dose of a mood stabilizer (such as lithium) was increased.

Herbal or natural supplements, such as St. John's wort (Hypericum perforatum), have not been well studied, and little is known about their effects on bipolar disorder. Because the U.S. Food and Drug Administration (FDA) does not regulate their production, different brands of these supplements can contain varying amounts of the active ingredient. Before trying herbal or natural supplements, it is important to discuss them with your doctor. There is evidence that St. John's wort can reduce the effectiveness of certain medications, including some used to treat human immunodeficiency virus (HIV)/ acquired immune deficiency syndrome (AIDS), heart disease, cancer, as well as oral contraceptives. In addition, like prescription antidepressants, St. John's wort may cause a switch into mania in some individuals with bipolar disorder, especially if no mood stabiliser is being taken.