Abstract

Objective: Individuals with schizophrenia display neurocognitive deficits including deficits in reward learning; a dopamine mediated activity. However, studies of reward learning are limited because participants are often evaluated when treated with medications that are strong dopamine antagonists that would be expected to negatively impact reward learning performance. The current study addresses this matter in medicated and drug-free individuals diagnosed with schizophrenia. Method: Participants included a schizophrenia group stabilized on haloperidol (n = 27) and a normal control group (n = 17). Both groups were evaluated with the WCST on two occasions separated by 3 weeks. After the initial assessment, 13 individuals with SZ were gradually withdrawn from haloperidol in a double blind, and were drug-free at the time of the second evaluation. Responses on the first four cards of the WCST were examined to assess reward learning. Data were archival and all study procedures were approved by the IRB at the time of data collection. Participants with SZ provided informed consent prior to completing any study procedures and were inpatients throughout the study. Results: Mixed model ANOVA examining the group (3) by assessment (2) by WCST card (4) effects indicated a significant group by card interaction effect, such that the two schizophrenia groups had lower performance across time intervals compared to controls. Conclusion(s): Results suggest that reinforcement learning as measured by the WCST was not affected by D2 receptor antagonism. More sophisticated neuroscience based approaches to assessment of reward learning might produce different findings, and so should be investigated in future studies.