Functional neural substrates of self-reported physical anhedonia in non-clinical individuals and in patients with schizophrenia

Background: Anhedonia is a negative symptom of schizophrenia that has a detrimental impact on functioning and quality of life. Anhedonia also represents a vulnerability marker for schizophrenia when measured in non-clinical individuals. The investigation of the neural correlates of anhedonia in schizophrenia and non-clinical individuals could provide key insights on the pathophysiology of negative symptoms, as well as on the characterization of neural markers of vulnerability. Methods: Thirty patients with schizophrenia and twenty-six non-clinical individuals were recruited. We used an event-related functional Magnetic Resonance Imaging paradigm involving an emotional picture viewing task. For each group, separately, we correlated the regional BOLD signal changes during hedonic processing with the Chapman Physical Anhedonia Scale scores. An interaction analysis identified the neural correlates of anhedonia specific to schizophrenia. Results: We found that anhedonia severity in both groups was inversely correlated with the activity of a limited number of emotion-related regions, including the medial prefrontal cortex. The orbitofrontal cortex and putamen/ventral striatum activity was negatively correlated with anhedonia severity in people with schizophrenia only. Conclusions: The data first suggest that anhedonia severity is linked to a poor modulation of emotional/attentional brain regions during the processing of hedonic information. The link between anhedonia and the activity of the ventral striatum and orbitofrontal cortex found in schizophrenia could reflect the specific impairment of indirect factors, such as reward anticipation deficits, that influence the measurement of anhedonia severity through self-report questionnaires. (c) 2009 Elsevier Ltd. All rights reserved.