title: Obsessive-compulsive symptoms in patients with schizophrenia: a naturalistic cross-sectional study comparing treatment with clozapine, olanzapine, risperidone, and no antipsychotics in 543 patients.
abstract: OBJECTIVE
  To compare the prevalence of obsessive-compulsive symptoms (OCS) in a population of patients with schizophrenia taking clozapine, olanzapine, or risperidone or taking no antipsychotic medication.
  
  
  METHODS
  Baseline data of the Genetic Risk and Outcome of Psychosis study were collected between April 2005 and October 2008. We conducted a naturalistic cross-sectional study of 543 patients with schizophrenia and related disorders, who were recruited from multiple mental health centers, including inpatient and outpatient clinics, across The Netherlands. The patients met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria and were taking no antipsychotic medication or taking clozapine, olanzapine, or risperidone. OCS severity was measured with the Yale-Brown Obsessive Compulsive Scale. We compared patients to a sample of 575 healthy controls.
  
  
  RESULTS
  Prevalence of OCS in patients was significantly higher than in the control sample, 23.4% versus 4.9% (χ(2) = 73.8, P < .001). Patients taking clozapine reported OCS significantly more often during the last week (38.9%), when compared to patients taking olanzapine (20.1%, χ(2) = 10.02, P = .002) or risperidone (23.2%, χ(2) = 5.96, P = .015) and patients taking no antipsychotics (19.6%, χ(2) = 8.20, P = .004). Patients taking clozapine for 6 months or longer reported OCS significantly more often than patients taking clozapine for less than 6 months, 47.3% versus 11.8% (χ(2) = 6.89, P = .009).
  
  
  CONCLUSIONS
  Treatment with clozapine in patients with schizophrenia is associated with a higher prevalence of OCS, especially when patients have been taking clozapine for 6 months or longer. We cannot rule out the possibility that this association is related to illness characteristics. Patients treated with risperidone or olanzapine or without treatment with antipsychotic medication had comparable prevalence of OCS, all significantly higher than the control sample.
authors.affiliation: Academic Medical Centre University of Amsterdam, Department of Psychiatry, Amsterdam, The Netherlands.
authors.forename: Albertine A
authors.initials: AA
authors.lastname: Scheltema Beduin
authors.forename: Marije
authors.initials: M
authors.lastname: Swets
authors.forename: Marise
authors.initials: M
authors.lastname: Machielsen
authors.forename: Nikie
authors.initials: N
authors.lastname: Korver
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000009:adverse effects* / Q000627:therapeutic use*; D016022:Case-Control Studies; D015984:Causality; D003024:Clozapine / Q000009:adverse effects* / Q000627:therapeutic use*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands; D009771:Obsessive-Compulsive Disorder / Q000139:chemically induced* / Q000453:epidemiology* / Q000235:genetics; D000077152:Olanzapine; D011569:Psychiatric Status Rating Scales; D018967:Risperidone / Q000009:adverse effects* / Q000627:therapeutic use*; D012559:Schizophrenia / Q000188:drug therapy* / Q000453:epidemiology* / Q000235:genetics; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D001569:Benzodiazepines; D003024:Clozapine; D018967:Risperidone; D000077152:Olanzapine