RESUMO
BACKGROUND: Obsessive-compulsive disorder (OCD) is a potentially debilitating disease that affects 1-4% of the general population. It is characterized by the presence of obsessions and compulsions which interfere with the individual's life and functioning. Although conventional treatments such as drug therapies and cognitive behavioral therapy exist for OCD, these treatments are not universally successful and can cause side effects, which has created a demand for alternative and complementary therapies. METHODS: In this review, we summarize randomized clinical trials on the effectiveness of herbal medicines for the treatment of OCD, and review the possible mechanisms of action for these medicines. A search in PubMed, Scopus, and The Cochrane Library found 1022 studies, of which 7 were included in our review. RESULTS: The studies that we found were conducted over 6 to 12 weeks, and had an average sample size of 37. The plant species studied included Crocus sativus, Echium amoenum, Hypericum perforatum, Silybum marianum, Valeriana officinalis, and Withania somnifera. The trials demonstrated the effectiveness of all plants as treatments for OCD except H. perforatum. The phytochemicals found in these plants produce their effects through a variety of means such as inhibiting the reuptake of monoamines, GABAergic effects, and neuroendocrine modulation. The small number of studies and their small sample sizes, poor methodology, and lack of replication highlight the need for further research into herbal medicines for the treatment of OCD. CONCLUSION: Overall, herbal medicines can be used as stand-alone therapies for OCD or in conjunction with other methods.