Preliminary evidence that individuals with remitted alcohol use disorder and major depressive disorder exhibit enhanced neural responses to reward: An EEG study

Introduction: Disruptions in neural responses to reward are implicated in risk for Alcohol Use Disorder (AUD) and Major Depressive Disorder (MDD). It is not clear whether these findings extend to those in remission from AUD and MDD, a critical question as studies of remission can (a) rule out effects due to current symptoms, and (b) can reveal potential trait-like differences.Methods: Individuals with and without remitted AUD (rAUD) and/or rMDD (rMDD) were drawn from a larger study to create four groups: rAUD (n = 54), rMDD (n = 66), rAUD + rMDD (n = 53), and a community control group (CCG; n = 81). Participants completed a validated monetary reward task during electroencephalogram (EEG). Multilevel models examined group differences in event-related potentials and time-frequency indices of reward and loss responsiveness, namely, reward positivity (RewP), feedback negativity (FN), reward-related delta power, and loss-related theta power.Results: Analyses revealed that the rAUD + rMDD group had significantly higher reward-related delta activity than the three other groups (p-values < 0.01), which did not differ from each other. Sensitivity analyses revealed this relationship fell just above the threshold set for significance after controlling for residual current MDD and AUD symptoms (p =.05). There were no other group differences or significant interactions (p-values > 0.05).Conclusions: To our knowledge, this is the first study to show that individuals with remitted AUD and MDD demonstrate increased sensitivity to rewards compared to individuals with remitted AUD alone, MDD alone, and without AUD or MDD. These findings suggest heightened motivational salience to reward might be an important factor in comorbid AUD and MDD.