title: Obsessive-compulsive disorder in schizophrenia: epidemiologic and biologic overlap.
abstract: OBJECTIVE
  To examine the co-existence of obsessive-compulsive disorder (OCD) with schizophrenia in terms of epidemiology and overlapping biologic substrates.
  
  
  METHODS
  Review of the relevant literature.
  
  
  RESULTS
  There appears to be a significant prevalence of OCD in schizophrenia--higher than what would be expected on the basis of calculated comorbidity figures. There is significant overlap in the proposed functional circuits of OCD and schizophrenia, which may lead to co-expression of symptoms. Although there is overlap in neurotransmitter dysfunction, the interactions are complex, especially in regard to the serotonin and dopamine systems.
  
  
  CONCLUSIONS
  The expression of OCD in schizophrenia is complex but very intriguing. Theoretical hypotheses of the pathology of the 2 disorders now need to be tested in larger controlled trials.
authors.affiliation: Department of Psychiatry, University of Alberta.
authors.forename: P
authors.initials: P
authors.lastname: Tibbo
authors.forename: L
authors.initials: L
authors.lastname: Warneke
mesh_terms: D001921:Brain / Q000503:physiopathology; D015897:Comorbidity; D006801:Humans; D018377:Neurotransmitter Agents / Q000502:physiology; D009771:Obsessive-Compulsive Disorder / Q000453:epidemiology* / Q000503:physiopathology; D012559:Schizophrenia / Q000453:epidemiology* / Q000503:physiopathology