A Review of Herbal Medicines for Psychiatric Disorders

Objective: St. John's wort, kava, ginkgo biloba, and valerian are herbs that are frequently used to treat mental health issues. Methods: Articles about the use of herbs in psychiatry published after 1990 were found by Searching Medline. Sources cited in publications retrieved from The Medline search were analyzed in a secondary search. Results: Out of nine standardized and controlled trials, five demonstrated that St. John's wort was more effective than a placebo, while four found no difference in effectiveness when compared to antidepressant medications. It is unknown which components are pharmacologically active. Although kava has been shown to be effective as an anxiolytic in a number of double-blind, placebo-controlled trials, these studies had limited sample sizes, short treatment durations, and poorly defined patient populations. Ginkgo extracts have been used in 40 controlled trials to treat dementia, and all but one of them report clinically significant improvements in memory loss, focus, fatigue, anxiety, and depression. The majority of gingko research used nonstandard metrics, had small sample sizes, and poorly characterized patient populations. Gingko dramatically reduced cognitive function decline in dementia patients, according to a new well-designed multicenter study. Valerian has been demonstrated to increase subjective sleep quality and reduce nocturnal awakenings and sleep latency; however, some studies showed significant placebo effects, and in other cases, the positive effects did not manifest until two to four weeks into the course of treatment.