Insight and cognitive deficits in schizophrenia: evidence for a curvilinear relationship.

Both motivational and defect theories have been offered to explain variations in insight among schizophrenic individuals but the results of tests of these theories have been inconclusive and inconsistent. The present study was designed to test the hypothesis that both motivation and cognitive deficits affect insight, with a trade-off between the two processes, giving rise to quadratic relationships between insight and cognitive deficits. Twenty-six schizophrenic patients completed a battery of neuropsychological tests and participated in an interview designed to assess insight. In a multiple regression analysis predicting test results from insight scores, the linear component was non-significant while the quadratic component accounted for a highly significant 56% of the variance. Theoretical and clinical implications of this result are discussed briefly.