Exploring logical reasoning abilities in schizophrenia patients

OBJECTIVE: To assess deductive reasoning in schizophrenia patients with special reference to whether accuracy varies across type of stimulus problem. Previous research suggests that patients, unlike healthy controls, are insensitive to emotionally provocative (salient) problem content. METHOD: A syllogistic reasoning task consisting of five argument types varying in salience, congruence with commonly held beliefs and meaningfulness was administered along with standard intellectual and symptom measures to 25 schizophrenia patients and 26 healthy control participants. RESULTS: Patients performed below control participants in all reasoning task conditions, but group differences were non significant after controlling for IQ. There were no significant interactions between group and argument type in terms of reasoning accuracy and both patients and controls performed better when reasoning with belief congruent material. In addition, no relation between deduction and paranoid symptoms was found. CONCLUSION: Formal deductive reasoning abnormalities in schizophrenia are a reflection of the broadly based cognitive impairment documented in the illness.