Schizophrenia Bulletin Advance Access originally published online on July 15, 2008
Schizophrenia Bulletin 2008 34(5):848-855; doi:10.1093/schbul/sbn078
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Reinforcement and Reversal Learning in First-Episode Psychosis
2 Brain Mapping Unit, Department of Psychiatry, University of Cambridge, Cambridge, UK
3 CAMEO, Cambridgeshire and Peterborough Mental Health Partnership NHS Trust
4 Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
5 Department of Psychiatry, University of Cambridge, Cambridge, UK
6 Cambridge Cognition Limited, Cambridge, UK
1 To whom correspondence should be addressed; Brain Mapping Unit, Department of Psychiatry, University of Cambridge, Box 255 Addenbrooke's Hospital, Cambridge CB2 2QQ, UK; tel: +44-0-1223-764676, fax: +44-0-1223-764675, e-mail: gm285{at}cam.ac.uk.
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 
= 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.
Keywords: neuropsychology / cognitive function / schizophrenia / orbitofrontal cortex / ventral striatum / set shifting