The extract of the St. John’s Wort flower is commonly used for treating depression. It is particularly popular in Europe. After numerous controlled trials, the research is still inconsistent and many positive studies were poorly designed. If it does have active antidepressant properties, they are associated with the chemical hyperforin, and a clinical-grade extract is considered to have not less than 5% hyperforin.
While I would not recommend against St. John’s Wort, there are other natural treatments with much stronger evidence.
Research
St. John’s Wort
Laakmann G, Schule C, Baghai T, Kieser M. St. John’s wort in mild to moderate depression: the relevance of hyperforin for the clinical efficacy. Pharmacopsychiatry. 1998;31:S54-S59.
In a randomized, double-blind, placebo-controlled, multicenter study, the clinical efficacy and safety of two different extracts of St. John’s wort were investigated in 147 male and female outpatients suffering from mild or moderate depression according to DSM-IV criteria. The therapeutic effect of St. John’s Wort in mild
to moderate depression was found to depend on its hyperforin content. Extracts of 5% hyperforin outperformed placebo at a significant level, while those of 0.5% hyperforin did not.
KIM, H. STRELTZER, J. GOEBERT, D. St. John’s Wort for Depression: A Meta-Analysis of Well-Defined Clinical Trials. Journal of Nervous & Mental Disease. 187(9):532-538, September 1999.
Studies concluding that St. John’s wort (Hypericum perforatum) is an effective antidepressant can be challenged due to questionable methodology. We attempt to correct this by a meta-analysis utilizing only well-defined clinical trials. Controlled, double-blind studies using strictly defined depression criteria were analyzed by the rate of change of depression and by the number of “treatment responders.” Rates of side effects and dropouts were also analyzed. Hypericum was 1.5 times more likely to result in an antidepressant response than placebo and was equivalent to tricyclic antidepressants (TCAs). The meta-analysis also showed that there was a higher dropout rate in the TCA group and that the TCAs were nearly twice as likely to cause side effects, including those more severe than hypericum. Hypericum perforatum was more effective than placebo and similar in effectiveness to low-dose TCAs in the short-term treatment of mild to moderately severe depression. However, design problems in existing studies prevent definitively concluding that St. John’s wort is an effective anti-depressant.
Shelton RC, Keller MB, Gelenberg A, et al. Effectiveness of St. John’s wort in major depression: a randomized controlled trial. JAMA. 2001;285(15):1978-86.
Found no specific antidepressant effects for St. Johns Wort beyond placebo.
