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.