This cutting-edge new volume comprises a selection of review articles carefully culled from the proceedings of the conference "Obsessive-Compulsive Behavior Spectrum Disorders: Refining the Research Agenda for DSM-V," one of a series convened by the American Psychiatric Association in collaboration with the World Health Organization and the U.S. National Institutes of Health to address the future of psychiatric diagnosis. The book reflects the conference's focus on those disorders that cross current diagnostic categories and identifies and analyzes the changing definitions, boundaries, and linkages among diverse conditions characterized by obsessive-compulsive behaviors. As the book emphasizes, research into the pathogenesis of obsessive-compulsive disorder increasingly supports reclassification out of the anxiety disorders and into a separate group of obsessive-compulsive–related disorders. In addition, the supplementation of the categorical diagnostic approach with a dimensional approach of assessing obsessive-compulsive symptom domains may help psychiatrists better understand the relationship between these disorders. Obsessive-Compulsive Spectrum Disorders: Refining the Research Agenda for DSM-V offers clinicians, academicians, and nosologists an in-depth look at how obsessive-compulsive phenomena are represented in the current diagnostic system and how DSM-V might better address the needs of patients with these disorders.