BDNF G196A polymorphism reduces the expression of the gene and activates apoptotic pathway [48, 49] and in other populations as US Caucasians, American Indian, African American, Chinese a significant association of this polymorphism was shown with depression cases [50–52] and several psychiatric disorders such as anxiety, obsessive compulsive disorder, depression, schizophrenia, psychosis and eating disorder [36, 53]. The gene discussed is BDNF; the disease is obsessive-compulsive disorder.