Theory of mind and unawareness of illness in schizophrenia: is poor insight a mentalizing deficit?

This study investigates the impact of theory of mind (ToM) deficits on poor insight in schizophrenia. The scale for unawareness of mental disorder (SUMD) was administered to 58 stable outpatients with schizophrenia. First and second order false belief tasks, the Eyes test and a battery of nonToM cognitive measures were administered. The Second order false belief task was the best predictor of each global insight and symptom attribution scores of the SUMD. ToM tasks explained the substantial amount of the variance (ranging from 22.5% to 29.9%) for the insight scores and classified the significant amount of the patients who were aware of the illness correctly. WCST perseveration scores did not contribute to insight scores beyond that contributed by second order false belief tasks. The Second order ToM tasks seems to have critical importance for the awareness of the disorder. Beyond more direct self-evaluation, the awareness of the disorder and its consequences may also require the ability to evaluate the self from the perspective of others. "Understanding the others' belief about another person" may be conceptually very similar to "understanding the others' belief about self" (instead of another person).