The relationship between self-referential processing-related brain activity and anhedonia in patients with schizophrenia.

Despite the possible relationship between impaired self-referential processing and anhedonia, it has not yet been investigated. This study investigated an abnormality in brain activation associated with self-referential processing and its relationship with anhedonia in schizophrenia, specifically in self-related brain regions of interest. Twenty patients with schizophrenia and 25 controls underwent functional magnetic resonance imaging while rating the degree of relevance between faces (self, familiar other, or unfamiliar other) and words (positive, negative, or neutral). Brain activation in self-related regions, including the ventral and dorsal medial prefrontal cortices, anterior cingulate cortex (ACC), posterior cingulate cortex, precuneus, and insula, were compared between groups and their correlations with anhedonia level were calculated. Compared to controls, patients were less likely to rate negative words as irrelevant for the self face. Patients showed significantly increased activation in the ACC and precuneus compared to controls, irrespective of conditions. ACC activity in the self-neutral word condition was positively correlated with anhedonia score in patients. These results suggest that patients with schizophrenia may have an abnormality in the self-related cortical midline structures and particularly, abnormal ACC activation may be involved in anhedonia. Disrupted self-referential processing may be a possible cause of anhedonia in schizophrenia.