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 conce ived as selection and bringing 'on line' internal representations of the ta sks that can be used to mediate goal-appropriate behavioral responses. Impa irment in contextual reasoning is thought to play a key role in the pathoph ysiology and symptom formation of schizophrenia. The Cognitive Bias Task (C BT) has recently been designed and is thought to activate contextual reason ing. A study for applying this method to schizophrenic patients and healthy control subjects has been carried out. The data show that a large percenta ge of the schizophrenic subjects (87.5%) do not use a context-dependent pro cedure for reasoning. There was a gender difference in CBT performance in t he healthy control group, with more females than males using a context-inde pendent procedure, but not in patients. These findings appear to be in agre ement with the body of literature supporting the hypothesis that schizophre nic patients utilize a more uneconomic data-driven information-processing p rocedure. The study of contextual reasoning seems to allow the identificati on of a fundamental cognitive process and/or crucial regions or circuits th at further research could demonstrate parsimoniously account for large part s of the heterogeneous cognitive deficits of schizophrenia. (C) 1999 Publis hed by Elsevier Science B.V. All rights reserved.