Neural Responses to Reward and Psychosis Dimensions

Background and Hypothesis: Deficits in motivational drive, reinforcement learning, and reward prediction have been implicated in psychotic disorders. Electroencephalography (EEG) measures of these processes have demonstrated inconsistent relationships with psychotic disorders. The present study addressed key limitations in the literature and examined the association between multiple EEG neural responses to reward and different psychosis dimensions. Study Design: The sample included 362 adults (age M = 49.87, 42.3% female): 169 with a history of hospitalization for a psychotic disorder and 193 demographically matched with no history of a psychotic disorder. Participants completed a monetary guessing task, and we measured the time-domain reward positivity (RewP) as well as time-frequency delta activity to win and theta activity to loss. Participants also completed clinical interviews, questionnaires, and neuropsychological measures. Study Results: Categorical analyses indicated no group differences in the RewP, but participants with schizophrenia or schizoaffective disorder had more blunted delta activity to win and theta activity to loss. Dimensional analyses indicated more blunted RewP, delta activity to win, and theta activity to loss were associated with greater psychosis dimension scores. More blunted delta activity to win was also associated with greater lower-order detachment and higher-order general psychopathology dimension scores. Executive functions mediated the relationship between both delta and theta activity and the psychosis dimension. Conclusions: Blunted EEG time-domain and time-frequency neural responses to reward are associated with dimensional representations of psychosis. The study also highlights the importance of cognitive deficits when examining the neural response to reward and psychosis.