Tuesday 20th December 2011

Silybum extract effective in Obsessive Compulsive Disorder

Obsessive Compulsive Disorder (OCD) is a neuropsychiatric (anxiety) disorder, characterised by obsessive thoughts and compulsive actions. Treatment that is prescribed for OCD, such as cognitive behavioural therapy, is inadequate, often has annoying adverse effects, does not always give an adequate result, or loses its effectiveness over time. Iranian scientists hope to have found a suitable and safe alternative in Silybum marianum extract. Recently, in a randomised double-blind pilot study they demonstrated that, in OCD, Silybum extract has the same level of effectiveness as the standard treatment with the SSRI (selective serotonin reuptake inhibitor) fluoxetine.

Fifty-five adults with OCD (diagnosis according to DSM-IV-TR and a Yale-Brown score ≥ 21 points) took Silybum (3 x 200 mg seed extract/day) or fluoxetine (3 x 10 mg/day) for an eight week period. For a period of six weeks prior to the study, the participants either received no medicine or (behavioural) therapy for OCD. Silybum extract and fluoxetine were both effective for obsessive and compulsive symptoms and effected a comparable (strong-significant) decrease in the Yale-Brown score; in the Silybum group this fell by an average of 11 points and in the fluoxetine group by an average of 12.5 points. In comparison to fluoxetine, it took one additional week for the effects of Silybum extract to become evident.

Silybum is widely known as a liver herb, but in addition has antioxidative, anti-inflammatory, antidiabetic, sedative and antidepressant effects. There are signs that the seed extract of Silybum, which is rich in silymarin (a mixture of flavonolignans), increases the serotonergic activity in the brain. In Iran, the use of Silybum extract in Obsessive Compulsive Disorder is not unknown, but this is the first time that this use of Silybum extract has been evaluated in a clinical study. Considering the positive result, the scientists are arguing in favour of a larger scale and longer study into the effectiveness of Silybum extract in OCD.

Sayyah M, Boostani H, Pakseresht S et al. Comparison of Silybum marianum (L.) gaertn. with fluoxetine in the treatment of obsessive-compulsive disorder. Prog Neuropsychopharmacol Biol Psychiatry. 2010;34(2):362-5.