title: The internal and external boundaries of obsessive-compulsive disorder.
abstract: OBJECTIVE
  This study aims to explore the internal and external boundaries of obsessive-compulsive disorder (OCD).
  
  
  METHODS
  Selected literature is reviewed.
  
  
  RESULTS
  Prevalence and incidence estimates for OCD vary markedly according to diagnostic criteria applied. External boundaries of the disorder are permeable, with a large degree of overlap with other psychiatric disorders, and an association with certain neurological disorders. Some cases of OCD appear to have a neurodevelopmental origin.
  
  
  CONCLUSIONS
  Further delineation of disorders characterised by obsessional and compulsive symptoms can inform models of aetiology, pathophysiology and treatment.
authors.affiliation: Mental Health, Fremantle Hospital & Health Service, Western Australia, Australia. David.Castle@health.wa.gov.au
authors.forename: D J
authors.initials: DJ
authors.lastname: Castle
authors.forename: A
authors.initials: A
authors.lastname: Groves
mesh_terms: D006801:Humans; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D015995:Prevalence