title: Stable cognitive deficits in schizophrenia patients with comorbid obsessive-compulsive symptoms: a 12-month longitudinal study.
abstract: BACKGROUND
  Amongst schizophrenia patients, a large subgroup of up to 25% also suffers from comorbid obsessive-compulsive symptoms (OCSs). The association between comorbid OCSs in these patients and neuropsychological impairment remains unclear and somewhat contradictory. Longitudinal approaches investigating the stability of OCS-associated cognitive deficits are missing.
  
  
  METHODS
  Thirty-seven patients with schizophrenia and comorbid OCSs and 43 schizophrenia patients without OCS were assessed with a comprehensive cognitive test battery and compared at baseline and, again, 12 months later.
  
  
  RESULTS
  Schizophrenia patients with comorbid OCSs showed significant pronounced deficits, with increasing effect sizes over the 12-month assessment period in specific cognitive areas such as visuospatial perception and visual memory (WAIS-R block design, Rey-Osterrieth Complex Figure Test), executive functioning (perseveration in the Wisconsin Card Sorting test), and cognitive flexibility (Trail Making test B). These cognitive domains are correlated with OCS severity and are known to be candidate cognitive domains in obsessive-compulsive disorder (OCD).
  
  
  CONCLUSIONS
  OCSs in schizophrenia is associated with specific and longitudinally stable cognitive deficits, strongly arguing for at least partially overlapping neurobiological mechanisms with OCD. Prospective studies involving patients with at-risk mental states for psychosis are necessary to decipher the interaction of cognitive impairment and the clinical manifestations of schizophrenia and OCSs. This might facilitate the definition of patients at high risk for OCSs, an early detection of subclinical levels, therapeutic interventions, and clinical monitoring.
authors.affiliation: To whom correspondence should be addressed; Central Institute of Mental Health, Department of Psychiatry and Psychotherapy, Medical Faculty Mannheim, University of Heidelberg, PO Box 12 21 20, D-68072 Mannheim, Germany; tel: 0049-621-1703-2523, fax: 0049-621-1703-1205, e-mail: frederike.schirmbeck@zi-mannheim.de.
authors.forename: Frederike
authors.initials: F
authors.lastname: Schirmbeck
authors.forename: Franziska
authors.initials: F
authors.lastname: Rausch
authors.forename: Susanne
authors.initials: S
authors.lastname: Englisch
authors.forename: Sarah
authors.initials: S
authors.lastname: Eifler
authors.forename: Christine
authors.initials: C
authors.lastname: Esslinger
authors.forename: Andreas
authors.initials: A
authors.lastname: Meyer-Lindenberg
authors.forename: Mathias
authors.initials: M
authors.lastname: Zink
mesh_terms: D000328:Adult; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009771:Obsessive-Compulsive Disorder / Q000453:epidemiology / Q000503:physiopathology*; D012559:Schizophrenia / Q000453:epidemiology / Q000503:physiopathology*; D012720:Severity of Illness Index
keywords: cognitive deficits; comorbidity; neuropsychology; obsessive-compulsive symptoms; psychosis; schizophrenia