Traditional Chinese medicine, has been used to treat patients with neuropsychiatric disorders. The Chinese term "xiao yao"means wandering free, which implies its anti-depressive effects.

The formula first appeared in Song Dynasty (between 960 and 1279 AD.) in a TCM classic He Ji Ju ). It was said to relieve muscular pain, dizziness, uneasiness, hot flashes, extreme sweating, insomnia, decreasing appetite and abnormal menstrual symptoms. In modern times, it has been used to treat many neuropsychiatric disorders, as well as liver diseases.

Literature shows that the formula has been shown to relieve panic attacks, anticipatory anxiety and agoraphobia. It has been used to treat irregularity of menstruation and anxiety involved with a menstrual cycle.

When used as an adjunct to carbamazepine (carbamazepine is an anticonvulsant and mood stabilizing drug, used primarily in the treatment of epilepsy and bipolar disorder. It is also used to treat schizophrenia and trigeminal neuralgia) in patients with bipolar disorders, the Kamo-shoyo-san combo treatment resulted in significantly greater clinical response rate in depressed patients. Kamo-shoy-san has proved to provide additive beneficial effects in bipolar patients, particularly for those in the depressive phase.

A group of scientists at the Department of Neuropsychiatry, School of Medicine, Paik Inje Memorial Clinical Research Institute, Inje University, Korea conducted the study and its results will be published later this year in the medical journal Psychiatry and Clinical Neurosciences.

In the present study, the anti-depressant-like effects and mechanism of action were investigated. Male Sprague-Dawley rats were given 10-fold or 20-fold the typical human daily dosage. Immobility time was measured by the forced swimming test, and hippocampal neurogenesis was quantified under immobilization stress.