Cross-cutting issues and future directions for the OCD spectrum.

The research planning agenda for DSM-V examined possible similarities in phenomenology, comorbidity, familial and genetic features, brain circuitry, and treatment response between obsessive-compulsive disorder (OCD) and several related disorders that are characterized by repetitive thoughts or behaviors. Such data support a re-examination of the DSM-IV-TR classification of OCD and the anxiety disorders, with possible inclusion of a group of obsessive-compulsive spectrum disorders (OCSDs) in DSM-V. Various disorders were systematically examined for inclusion in such a grouping, and later a smaller number were determined to meet threshold criteria for inclusion in the OCSDs. The disorders that were originally examined included OCD, obsessive-compulsive personality disorder (OCPD), Tourette's syndrome (TS) and other tic disorders, Sydenham's chorea, Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS), trichotillomania (TTM), body dysmorphic disorder (BDD), autism, eating disorders, Huntington's and Parkinson's disease, impulse control disorders, as well as substance and behavioral addictions. Certain disorders such as BDD, OCPD, TS, and TTM share many commonalities with OCD in phenomenology, comorbidity, familial and genetic features, brain circuitry, and treatment response. Other disorders, such as the impulse control disorders (ICDs) share some common features with OCD, but also differ in many ways as well. The articles presented in this issue of Psychiatry Research are a result of this international collaboration, which examined diagnostic and classification issues of OCSDs for DSM-V in a conference titled "The Future of Psychiatric Diagnosis: Refining the Research Agenda: Obsessive-Compulsive Behavior Spectrum" held in June 2006 at the American Psychiatric Association's headquarters in Arlington, VA.