Although obsessive-compulsive disorder（OCD）is classified as an anxiety disorder in the DSM-IV, recent considerations for a reclassification into an obsessive-compulsive spectrum disorders（OCSDs）cluster are gaining prominence. Hollander and colleague indicate that similarities in symptomatology, course of illness, patient population, and neurocircuitry of OCD and OCSD are supported by comorbidity, family, and neurological studies, which also offer a critical re-evaluation of the relationship between OCD and anxiety disorders. In February 2010,as a consequence,members of the DSM-5 Task Force and Work Groups have updated draft DSM-5 and have added many diagnostic-specific severity measures, including the Anxiety, Obsessive-Compulsive-Related, and Trauma-Related Disorders. Recently, however, there are some results indicated that support the current association of OCD with other anxiety disorders rather than with OCSDs. Thus, controversy surrounds the classification of OCSD symptoms.
 In this review,we investigated the relationship of OCD,OCSDs,and anxiety disorders to answer the question of where OCD should be located in the diagnostic system.