187. Modeling Anhedonia in Schizophrenia: A Stochastic Dynamical Systems Approach

Abstract

Background: Anhedonia, traditionally defined as a diminished capacity to experience pleasure, has long been considered a core feature of schizophrenia. However, modern evidence indicates that anhedonia is better considered a reduction in the frequency of approach behavior than diminished intensity of pleasure when engaged in activities. The current study used Ecological Momentary Assessment (EMA) to examine whether schizophrenia patients display abnormalities in the temporal dynamics of emotion that prevent fully intense in-the-moment positive emotions from translating into approach behavior. Methods: Participants included 28 outpatients with schizophrenia and 28 healthy controls who completed prospective, retrospective, and in-the moment EMA reports of emotional experience at multiple time points in the day, over the course of 6 days. Mathematical models, including network analysis and Markov chain analysis, were applied to the EMA data to evaluate stochastic dynamic changes in emotional states to determine mechanisms underlying failures to sustain positive emotion across time. Results: Results indicated no group differences for intensity of in-the-moment, retrospective, or prospective reports of positive emotion. However, mathematical models indicated that SZ had deficits in the ability to sustain positive emotion over time, which resulted from failures in augmentation (i.e., the ability to maintain or increase the intensity of positive emotion from time t to t+1) and blunting (i.e., when emotions at time t+1 are opposite in valence from emotions at time t, resulting in a decrease in the intensity of positive emotion over time) that predicted reductions in approach behavior. Conclusion: Findings suggest that abnormalities in the temporal dynamics of emotion are central features of schizophrenia that predict reduced approach behavior, providing a novel mechanistic account of anhedonia as it occurs in the real world.