Decreased Self-Concept Clarity in People with Schizophrenia.

Disturbances in the perception of self are thought to be central to the development of psychosis. Self-concept clarity (SCC) is the extent to which one's beliefs about oneself are internally consistent, stable, and clear. Participants with schizophrenia (N = 54) and healthy controls (N = 32) completed the Me Not-Me Decision Task (MNMDT), in which they decided whether 60 adjectives (30 pairs of antonyms) did or did not describe themselves. SCC is conceptualized as the number of consistent responses. Participants also completed the Self-Concept Clarity Scale (SCCS). Compared to healthy controls, participants with schizophrenia scored lower on the MNMDT and SCCS, and scores were negatively correlated with positive and negative symptoms. In a simultaneous regression, SCCS scores were uniquely associated with positive symptoms, whereas MNMDT scores were uniquely associated with negative symptoms. This suggests that people with schizophrenia have decreased self-concept clarity that is related to positive and negative symptoms.