Anhedonia and emotional experience in schizophrenia: neural and behavioral indicators.

BACKGROUND: Emotional impairments such as anhedonia are often considered key features of schizophrenia. However, self-report research suggests that emotional experience in response to affect-eliciting stimuli is intact in schizophrenia. Investigation of neural activity during emotional experience may help clarify whether symptoms of anhedonia more likely reflect alterations of in-the-moment hedonic experience or impairments in other aspects of goal-directed behavior.
METHODS: Forty individuals with DSM-IV-TR schizophrenia or schizoaffective disorder and 32 healthy control subjects underwent functional magnetic resonance imaging while making valence and arousal ratings in response to emotional pictures, words, and faces. Blood oxygen level-dependent responses were compared between patients and control subjects and were correlated with questionnaire measures of anhedonia.
RESULTS: Patients showed some evidence of blunted valence but not arousal ratings in response to emotional stimuli compared with control subjects. Higher anhedonia scores were associated with blunted valence ratings in both groups and fully mediated the group differences in valence ratings. Functional activity was largely intact in patients, except for regions in right ventral striatum and left putamen, which showed reduced responses to positive stimuli. Higher anhedonia was associated with reduced activation to positive versus negative stimuli in bilateral amygdala and right ventral striatum in patients and in bilateral caudate in control subjects.
CONCLUSIONS: Increased anhedonia is associated with a reduced experience of valence in both patients and control subjects, and group differences in experienced valence are likely driven by individual differences in anhedonia. Reduced activation of the striatum and amygdala may contribute to symptoms of anhedonia by failing to signal the salience of positive events. Copyright 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.