Deficits in Analytic and Common-Sense Reasoning in Schizophrenia.

Human rationality has a dual nature including analytic and common-sense thinking. Symptoms of schizophrenia have been suggested to be related to deficits in these aspects of logical reasoning. However, empirical studies investigating logical reasoning errors in schizophrenia and their clinical and neurocognitive correlates are scarce. Formal thought disorder and theory of mind (ToM) might be particularly important for understanding logical reasoning errors in schizophrenia. The current study compared the performances of 80 patients with schizophrenia with those of 49 healthy controls on syllogistic and counterfactual reasoning tasks and investigated clinical, neuropsychological, and social cognitive correlates of logical reasoning in schizophrenia. Patients with schizophrenia were impaired in both analytic and common-sense thinking. ToM impairment was a significant predictor of analytic reasoning abilities in schizophrenia. Executive functions and verbal memory were also significantly associated with analytic reasoning in schizophrenia. Further studies investigating logical reasoning errors in the early phases of the illness are needed.