title: Reinforcement and reversal learning in first-episode psychosis.
abstract: BACKGROUND
  Abnormalities in reinforcement learning and reversal learning have been reported in psychosis, possibly secondary to subcortical dopamine abnormalities.
  
  
  METHODS
  We studied simple discrimination (SD) learning and reversal learning in a sample of 119 first-episode psychosis patients from the Cambridge early psychosis service (CAMEO) and 107 control participants. We used data on reinforcement learning and reversal learning extracted from the Cambridge Neuropsychological Test Automated Battery Intradimensional-Extradimensional shift task, which measures cognitive flexibility but also involves simple reinforcement learning (SD learning) and reversal learning stages. We also gathered diagnostic information to examine whether there were any differences between patients ultimately diagnosed with schizophrenia-spectrum disorders and those diagnosed with affective psychosis.
  
  
  RESULTS
  Psychosis patients demonstrated deficits in simple reinforcement learning (SD learning) and in reversal learning, with no differences between affective psychosis and schizophrenia-spectrum psychosis. There was a significant modest correlation between reversal errors and negative symptoms (Spearman rho = 0.3, P = .02).
  
  
  CONCLUSIONS
  There are reinforcement learning abnormalities in first-episode psychosis, which correlate with negative symptoms, suggesting a possible role for orbitofrontal cortex and ventral striatal pathology in the pathogenesis of motivational deficits in psychosis.
authors.affiliation: Brain Mapping Unit, Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK. gm285@cam.ac.uk
authors.forename: G K
authors.initials: GK
authors.lastname: Murray
authors.forename: F
authors.initials: F
authors.lastname: Cheng
authors.forename: L
authors.initials: L
authors.lastname: Clark
authors.forename: J H
authors.initials: JH
authors.lastname: Barnett
authors.forename: A D
authors.initials: AD
authors.lastname: Blackwell
authors.forename: P C
authors.initials: PC
authors.lastname: Fletcher
authors.forename: T W
authors.initials: TW
authors.lastname: Robbins
authors.forename: E T
authors.initials: ET
authors.lastname: Bullmore
authors.forename: P B
authors.initials: PB
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention; D005260:Female; D006801:Humans; D007859:Learning Disabilities / Q000453:epidemiology; D008297:Male; D011581:Psychological Tests; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology*; D012054:Reinforcement, Psychology; D012193:Reversal Learning