WESTPORT, Aug 30 (Reuters Health) - Controlled studies are showing at least some efficacy of different herbal preparations in treating psychiatric symptoms, according to Drs. Gabrielle Beaubrun and Gregory E. Gray, of the Martin Luther King, Jr.-Drew Medical Center in Los Angeles, California.

But because of the chemical complexity of herbal products, their lack of standardization, and the paucity of well-controlled studies comparing them with conventional medications, the researchers do not yet recommend herbal remedies over established conventional treatments.

Writing in the September issue of Psychiatric Services, they describe their literature search of studies conducted on herbal remedies since 1990. For St. John's wort, the literature search revealed nine of what the investigators call "well-controlled trials using standardized dosages and standard outcome measures," where side effects were "mild and uncommon."

The studies used 900 mg/day of an aqueous methanol extract of St. John's wort, compared either with placebo or with low dosages of maprotiline, imipramine and amitriptyline. In the five placebo controlled studies, 61% of subjects receiving the extract responded with at least a 50% decline in Hamilton Rating Scale for Depression, compared with 24% of those receiving placebo.

In the other studies, response to St. John's wort was not significantly different from the response to conventional antidepressants, but the authors note that "the studies were small, raising the possibility of type II error, and no placebo control groups were included."

Drs. Beaubrun and Gray similarly analyzed studies of kava, ginkgo, and valerian. Kava was demonstrated to be anxiolytic, but the studies had "ill-defined patient populations, small sample sizes, and short treatment duration." Forty controlled trials of gingko extracts showed significant improvement in memory loss, concentration, fatigue, anxiety and depressed mood, but the studies suffered limitations similar to those for kava.

Studies of valerian showed some efficacy in reducing sleep latency and improving subjective sleep quality, but placebo effects were also prominent.

(From Reutershealth)