title: Strategy implementation in obsessive-compulsive disorder and trichotillomania.
abstract: BACKGROUND
  The use of strategies to aid performance when undertaking neuropsychological tasks is dependent on intact fronto-striatal circuitry, and growing evidence suggests impaired spontaneous use of strategies in patients with obsessive-compulsive disorder (OCD). However, studies to date have not examined the effects of strategy training on task performance in OCD or in trichotillomania (compulsive hair-pulling, a condition that has been argued to share overlap with OCD in terms of phenomenology and co-morbidity).
  
  
  METHODS
  The ability to generate novel visuospatial sequences using a computer interface was examined before and after undertaking optimal strategy training in 20 OCD patients, 17 trichotillomania patients, and 20 controls (matched for age, education, and IQ).
  
  
  RESULTS
  OCD patients failed to improve ability to generate novel sequences above baseline despite successfully completing strategy training to the same extent as other groups. In contrast, performance of trichotillomania patients improved significantly after training to the same extent as controls. Groups did not differ on memory span, trial-by-trial action monitoring, or ability to generate novel visuospatial sequences prior to strategy training.
  
  
  CONCLUSIONS
  Strategy implementation deficits, suggestive of cognitive inflexibility and fronto-striatal dysfunction, appear integral to the neurocognitive profile of OCD but not trichotillomania. Future research should investigate cognitive flexibility in obsessive-compulsive spectrum disorders using a variety of paradigms, and clarify the contribution of specific neural structures and transmitter systems to deficits reported.
authors.affiliation: Department of Psychiatry, University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Cambridge, UK. src33@cam.ac.uk
authors.forename: Samuel R
authors.initials: SR
authors.lastname: Chamberlain
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Blackwell
authors.forename: Naomi A
authors.initials: NA
authors.lastname: Fineberg
authors.forename: Trevor W
authors.initials: TW
authors.lastname: Robbins
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Sahakian
mesh_terms: D000328:Adult; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology; D003342:Corpus Striatum / Q000503:physiopathology; D003710:Demography; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D010468:Perceptual Disorders / Q000175:diagnosis / Q000453:epidemiology; D013028:Space Perception; D014256:Trichotillomania / Q000453:epidemiology*; D014796:Visual Perception