Reward Processing in Binge Eating and Harmful Drinking: A Systematic Review.

OBJECTIVE: Binge eating and harmful drinking commonly co-occur, which worsens the physical and psychological consequences associated with either behavior alone. Reward processing alterations have been demonstrated among individuals who engage in binge eating or harmful drinking alone; however, there is limited understanding of how different components of reward processing might relate to both behaviors together and in isolation. The current systematic review aimed to consolidate knowledge on the shared and unique reward processes associated with binge eating and harmful drinking, with findings organized by reward construct and assessment method.

METHOD: The review was pre-registered (osf.io/njpyh). Databases were searched for empirical articles that included assessment of binge eating, harmful drinking, and reward processing. All search strategy, screening, quality assessment, and data extraction files are available (osf.io/4h6c5).

RESULTS: Relevant findings from 25 included articles were summarized and compared. Higher self-reported general and food- and alcohol-specific reward anticipation were associated with co-occurring and separate engagement in binge eating and harmful drinking. Prolonged engagement in either behavior was associated with increased habit-based reward learning.

DISCUSSION: This review highlights the potential clinical utility of incorporating assessment, monitoring, and management of elevated anticipatory reward responsiveness and altered reward learning into intervention strategies for binge eating and harmful drinking. Future studies investigating various components of reward processing with different reward types (e.g., food, alcohol, money) and more diverse samples are necessary to clarify the nature and specificity of reward processing alterations related to binge eating and harmful drinking.