Obsessive-Compulsive Disorder and Obsessive-Compulsive Spectrum Disorders: Diagnostic and Dimensional Issues

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. 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. This review examines potential classifications of OCD among the wider spectrum of affective disorders and at the interface between affective disorders and addiction. In addition, it has been suggested that the categorical diagnostic approach would be enhanced by an additional dimensional approach, including parameters such as stability of mood and ability to sustain attention. With further studies, it is ultimately the goal to define OCD and related disorders based on endophenotypes. Despite efforts in this field, there are several fundamental unresolved issues, including the question of which disorders should be grouped together in this category and which characteristics to include as their shared common features. A reclassification of OCD among the OCSDs would allow for better scrutiny of distinct obsessive-compulsive symptoms, as currently this disorder often goes undetected in patients who complain of a broad symptom of anxiety. Advantages and disadvantages of establishing OCSDs and its implications for diagnosis, treatment, and research are discussed.