Neuropsychology of the Social Brain Hypothesis of Schizophrenia: Symptoms, Personality and MRI Correlates

Abstract

We examined the social brain hypothesis in schizophrenia using a comprehensive battery of measures of intelligence, personality, and symptoms in a large sample of medicated, long-term, chronic patients. A smaller subset also had available MRI studies of superior temporal gyrus (STG) and fusiform gyrus (FG), regions that have been linked to social cognition in both healthy and clinical samples. Results indicated that patients divided into high-and low-IQ groups differed significantly on proxy measures of social cognition, specifically symptom ratings and personality test scores. That is, high-and low-IQ groups had similar levels of negative and positive symptoms, but showed opposite patterns for personality traits of neuroticism and openness, with the former reduced and the latter elevated in the high-IQ group. Likewise, for the entire sample, reduced neuroticism and elevated openness corresponded with higher ratings on the positive symptom of formal thought disturbance. MRI data also revealed evidence of distinct symptom-personality relationships marked by decreased gray matter volumes in the: (a) STG with increased positive symptoms of hallucinations and lower agreeableness and (b) FG with increased negative symptoms of social anhedonia and lower openness. Together, these behavioral and MRI data may help to define the nature of social cognitive disturbance in schizophrenia.