Many guides and references acknowledge that the traditonal botanical St. John’s Wort can be effective for mild to moderate depression.
However, a 2005 article in the British Medical Journal reported on a study that also found the herbal extract effective in cases of moderate to severe depression. The six-week study compared St. John’s Wort to Paxil, a prescription drug in the serotonin reuptake inhibitor (SSRI) class. The 251 participants in this study were psychiatric clinic outpatients with moderate to severe depression.
The investigators found a significant improvement in depressive symptoms among the study participants taking the botanical, and concluded that the St. John’s Wort extract showed at least as much effectiveness as the prescription drug, and with fewer adverse events (“side effects”).
Note: St. John’s Wort interacts with pharmaceuticals, so it’s not recommended if you are taking drugs such as protease inhibitors.
Reference: A Szegedi, R Kohnen, A Dienel, and M Kieser. Acute treatment of moderate to severe depression with hypericum extract WS 5570 (St John’s wort): randomised controlled double blind non-inferiority trial versus paroxetine. BMJ 2005;330:503 (5 March), doi:10.1136/bmj.38356.655266.82 (published 11 February 2005)