Obsessive-compulsive spectrum disorders in obsessive-compulsive disorder and other anxiety disorders

There has been debate about whether obsessive-compulsive disorder (OCD) should be classified as one of the anxiety disorders, or should rather be categorized with obsessive-compulsive spectrum conditions.

The question of where OCD should be located in the diagnostic system was addressed by investigating the relationship of OCD, obsessive-compulsive spectrum disorders (OCSDs), and anxiety disorders. We administered a structured diagnostic interview (the SCID-OCSD) for assessing putative OCSDs in patients who presented with a primary diagnosis of OCD, panic disorder with/out agoraphobia (PD) or social anxiety disorder (SAD) in an attempt to address the proposed differentiation of OCD from the other DSM-IV anxiety disorders.

Patients with OCD were significantly more likely to have multiple comorbid putative OCSDs than patients with PD or SAD. Some OCSDs, i.e. any tic disorder/Tourette's disorder as well as body-focused repetitive behaviors (self-injury, trichotillomania), and certain impulsive/reward-focused disorders (kleptomania, hypersexual disorder) were more common in OCD. Some of the putative OCSDs (e.g. hypochondriasis and body dysmorphic disorder) were more common in PD and SAD, respectively. Depression had equally high comorbidity with OCD, PD, and SAD, while generalized anxiety disorder and alcohol dependence were particularly associated with SAD.

These findings suggest that some putative OCSDs may be related to OCD, while some may have a closer relationship to other anxiety disorders. From a nosological perspective, it may be useful to include OCD and certain OCSDs under the rubric of an enlarged category of anxiety and OCSDs.