Phytotherapy and psychiatry: bibliometric study of the scientific literature from the last 20 years.

In diverse areas of therapy, including psychiatry, increasing interest in herbal medicine has been shown in recent years. Plants have a wide range of traditional uses, but only a few have been approved therapeutically. Moreover, to our knowledge, no bibliometric analyses on medicinal plants used in psychiatry have been carried out to date. We performed a bibliometric study on scientific publication related to phytotherapy in the psychiatry area during the period 1986-2006. Using the platform Embase.com, including the EMBASE and MEDLINE databases, we selected those documents including the descriptors plant*, herb*, phytotherapy*, phytomedicine*, pharmacognosy*, and psychiatry* (with all diagnostic criteria). The plants' indications were selected according to the PDR for Herbal Medicines. As a bibliometric indicator of the production, Price's Law was applied. Another indicator included was the national participation index (PI) for overall scientific production. A total of 21,409 original documents were obtained. Our data confirm a fulfillment of Price's Law related to scientific production on medicinal plants in Psychiatry. This was observed after we made a linear fit (y=135.08x-466.38; r=0.92) and another fit to an exponential curve (y=132.26e(0.1497x); r=0.99). The plants most widely mentioned in the psychiatric literature were St. John's wort (Hypericum perforatum L.; n=937) and ginkgo (Ginkgo biloba L.; n=694). The countries with the highest percentages of documents were the United States (29.44%), Germany (9.41%) and Japan (8.75%), and those with highest proportional PI were India (IPa=0.935) and China (IPa=0.721). Productivity on medicinal plants in the psychiatry area increased during the period 1986-2006. Nevertheless, documents about therapeutic herbs in this medical field are still relatively few in number.