N-methyl Glycine (Sarcosine) for the Treatment of Obsessive Compulsive Disorder (OCD)

Inclusion Criteria: * a primary OCD according to DSM-IV * at least 1 year's duration of OC symptoms and a minimum severity score of ≥16 on Yale-Brown Obsessive Compulsive Scale * drug naïve at study entry or * being free from psychotropic medication for at least 8 weeks at study entry,or * inadequately responded to ongoing psychotropic medications at study entry (defined by a Y-BOCS score of ≧16 despite treatment with maximum tolerated dose of a SRI medication for at least 8 weeks) Exclusion Criteria: * patients with moderate to severe depression defined by a 21-item Hamilton Depression Rating Scale score of \>17, * a history of bipolar disorder, schizophrenia, schizoaffective disorder, or other psychosis as defined by DSM-IV, or if they were at significant risk of suicide, and * with clinically significant organic disease including cardiovascular, hepatic, pulmonary, neurologic, metabolic, or renal disease