Obsessive-compulsive disorder belongs to anxiety disorders, with a prevalence of 2,5% in the general population. The pathogeny of the disorder includes a probable genetic component but of moderate importance. Neuroimaging studies showed a hyperactivity of the prefrontal cortex and the caudate nucleus which appears to reflect abnormalities in cerebral circuits. The pharmacological treatment of obsessive-compulsive disorder comprises in first line selective serotonin reuptake blocker antidepressants. Clomipramine (Anafranil), often considered as more effective represents a second choice due to its side-effects. The treatment generally requires high doses of antidepressants administered over a prolonged period. Several augmentation strategies have been proposed for resistant patients. Very recently, brain neurostimulation techniques using implanted electrodes have demonstrated their interest in case of failure of other treatment strategies.