Schizophrenic patients use context-independent reasoning more often than context-dependent reasoning as measured by the cognitive bias task (CBT): a controlled study

The processing of context is a relevant issue that is probably involved in many neurological and psychiatric conditions. Contextual reasoning is conceived as selection and bringing 'on line' internal representations of the tasks that can be used to mediate goal-appropriate behavioral responses. Impairment in contextual reasoning is thought to play a key role in the pathophysiology and symptom formation of schizophrenia. The Cognitive Bias Task (CBT) has recently been designed and is thought to activate contextual reasoning. A study for applying this method to schizophrenic patients and healthy control subjects has been carried out. The data show that a large percentage of the schizophrenic subjects (87.5%) do not use a context-dependent procedure for reasoning. There was a gender difference in CBT performance in the healthy control group, with more females than males using a context-independent procedure, but not in patients. These findings appear to be in agreement with the body of literature supporting the hypothesis that schizophrenic patients utilize a more uneconomic data-driven information-processing procedure. The study of contextual reasoning seems to allow the identification of a fundamental cognitive process and/or crucial regions or circuits that further research could demonstrate parsimoniously account for large parts of the heterogeneous cognitive deficits of schizophrenia. (C) 1999 Published by Elsevier Science B.V. All rights reserved.