CLINICAL-TRIALS WITH PHYTO-PSYCHOPHARMACOLOGICAL AGENTS

Phyto-psychopharmacological agents are extracts of plants with stimula ting or calming effects on the central nervous system. Phyto-psycho-ph armacological agents are among the most commonly prescribed herbal med icines in Germany. The efficacy and harmlessness of some of the prepar ations have been established by high quality clinical trials. Between 1975 and 1992, a total of 34 clinical studies involving some 2326 pati ents were published on the effects of Ginkgo special extract EGb 761 a nd LI 1370; to date, 28 clinical trials in 2120 patients have been und ertaken with alcoholic extracts of St. John's Wort. The therapeutic ef ficacy of kava and valerian extracts has been investigated in six and four controlled studies, respectively. In general, a high placebo effe ct is likely, which is why it is essential to include control groups i n these studies. A considerable advantage over synthetic psychopharmac ological agents is the low incidence of side effects, which in safety assessment studies is below 3%. The sharp increase in quality standard s for clinical trials has meant that only a few preparations have unde rgone large scale testing programs in accordance with international gu idelines. For other phyto-psychopharmacological agents, there is the d anger that no further clinical trials will be undertaken due to the ex cessively high standards now demanded.