Anhedonia, the diminished ability to experience pleasant emotions, is a common, treatment-resistant negative symptom of schizophrenia that is associated with the profound impairments in social functioning that characterize this disorder. Recent research has raised fundamental questions about the precise nature of this emotional disturbance. Informed by a neurobehavioral model of hedonic experience, this proposal examines the hypothesis that schizophrenia is characterized by impaired appetitive pleasure (derived from anticipating enjoyable experiences or """"""""wanting"""""""") but intact consummatory pleasure (experienced while engaged in enjoyable activities or """"""""liking""""""""). Stabilized schizophrenia outpatients and healthy control subjects will complete self-report questionnaires of trait appetitive and consummatory pleasure, as well as two electrophysiological paradigms that have been used to probe these aspects of hedonic experience in the basic affective science literature. Appetitive pleasure will be assessed with an emotional anticipation paradigm to examine the hypothesis that schizophrenia patients will demonstrate less Stimulus-Preceding Negativity (SPN) than healthy controls during the anticipation of pleasant visual stimuli, but comparable levels of SPN during anticipation of neutral and unpleasant stimuli. Consummatory pleasure will be assessed using an affective picture-viewing paradigm to examine the hypothesis that schizophrenia patients will demonstrate P300 and late positive potentials that are comparable to controls during direct exposure to pleasant and neutral visual stimuli, but greater P300 and late positive potentials than controls during direct exposure to unpleasant stimuli. This initial study will provide the groundwork for conducting more comprehensive evaluations of the neurophysiological underpinnings of anhedonia and other negative symptoms in schizophrenia. Anhedonia and other negative symptoms are associated with the profound impairments in independent living, vocational functioning, and social relationships that characterize schizophrenia. The development of novel treatments for anhedonia are therefore of particular public health significance, but such efforts are currently hampered by an inadequate understanding of its precise nature and physiological mechanisms. The proposed research will help guide the development of more effective treatments by using electrophysiological methods to evaluate whether anhedonia in schizophrenia primarily reflects impairment in the appetitive or the consummatory component of hedonic experience. ? ? ?
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