Although clinical trials are ongoing for this increasingly popular herbal supplement, it seems clear that for mild depression, St. John's wort can be an effective treatment. However, there are factors which indicate that this herb should not be used by persons who have bipolar disorder.
In February of 2000, the US Food and Drug Administration released a Public Health Advisory warning that there was a risk of dangerous interactions between St. John's wort and certain prescription medications. Researchers found that use of St. John's wort significantly reduces the effectiveness of some AIDS medications (indinavir and other antiretroviral agents). Because of the way St. John's wort operates in the body, the FDA also warned that it may also be unsafe to take it along with some common medications for heart disease, transplant rejection and cancer, among others. Drugs mentioned by name that are used in the treatment of mood disorders were:
- The tricyclic antidepressants imipramine (Tofranil), amoxapine (Asendin), and amitriptyline (Elavil);
- The anti-seizure medication carbamazepine (Tegretol), used as a mood stabilizer; and
- The cancer medication Tamoxifen, which is being studied as a mood stabilizer.
Too much of the neurotransmitter serotonin can produce a potentially dangerous condition. Camilla Cracchiolo, R.N., who is studying St. John's wort in depth, said, "In the letters I've personally received [regarding the herb and serotonin syndrome], the patients all reported a gradual onset of dizziness, cognitive difficulty, faintness when standing or walking, unsteadiness when walking, muscle spasms and racing heart beat." Because St. John's wort may increase the amount of serotonin available, combining the herb with an SSRI such as Prozac or Paxil is not recommended.
A Mania Trigger
It is well known that any antidepressant, when taken without a mood stabilizer, can set off a manic or hypomanic episode. Some people never exhibit mania at all until treated for depression with a triggering drug. Since St. John's wort acts as an antidepressant, researchers at Harvard Medical School and the University of Michigan have issued warnings regarding SJW as a possible triggering substance. Published case reports have documented several cases of sudden onset of mania in bipolar patients who were using the herbal supplement.
For a number of reasons, then, the bottom line with St. John's wort for persons with manic-depressive illness should be "Better safe than sorry." If you or someone you love who is bipolar insists on using this supplement, use extreme caution, notify your physician or psychiatrist, and be on the lookout for any complications.
Reference: Cracchiolo, Camilla. http://www.primenet.com/~camilla/STJOHNS.HTML (no longer online)