Serotonin reuptake inhibitors（SRI）are effective in the treatment of obsessive-compulsive disorder（OCD）. The response rate for SRI is approximately 50% and refractory OCD may exist. The effect of antipsychotics augmentation therapy has been established for this kind of patients. However,OCD is clinically and biologically heterogeneous neuropsychiatric disease and it will affect the response of pharmacotherapy. Several subtypes of OCD have been identified. Early onset OCD and hoarding symptoms dominant patients with OCD tend to resist SRI treatment. Antipsychotics augmentation with SRI is much effective for OCD with tic disorders.
 On the other hand, psychiatric disorders in obsessive-compulsive spectrum disorders（OCSD）have similar clinical symptoms, comorbidities, genetic factors, and neurobiological etiology. SRI is effective for patients with body dysmorphic disorder（BDD）in preoccupation with body appearance or sensation subgroup. The response of SRI in BDD is similar to OCD while that of eating disorders was different. Impulse control disorders will respond to opiate antagonist but not to SRI. This subgroup might have a characteristic of behavioral addiction. Antipsychotic agents are effective for neurological disorders including tic disorders,Tourette syndrome, and autistic spectrum disorders. Therefore, the dopaminergic pathophysiology might underlie in this subgroup. The main goal of DSM-V is to make diagnosis based on biological validity, and the treatment response is an important factor. Further studies are necessary for understanding the pathophysiology of OCSD.