Reward Deficits in Co-Occurring Social Anxiety and Depression: The Roles of Anhedonia, Boredom, Loneliness, and COVID-19 Social Restriction.

Prior research points toward reward deficits as crucial to the link between social anxiety disorder and major depressive disorder. However, studies have not explored specific types of reward deficits or how social-environmental factors may impact them. The current study examined whether the indirect effects of three reward deficits (anhedonia, boredom, and loneliness) accounted for the connection between social anxiety and depression. Questionnaires were collected in a sample of college students (N = 523) during the first year of the COVID-19 pandemic, allowing examination of environmental stressors (i.e., remote learning and current friend network size) on reward deficits. Indirect effect models showed that anhedonia, boredom, and loneliness each uniquely partly accounted for the association between social anxiety and depression (accounting for 20%, 38%, and 14% of the association, respectively), with boredom accounting for the largest proportion. Further, analyses suggested that anhedonia was associated with the social anxiety-depression link only among remote learners, while loneliness appeared to be only associated among students who had smaller friend networks. Findings highlight the importance of reward deficits in co-occurring social anxiety-depression symptoms. We present novel findings showing the strong role of boredom in the connection between social anxiety and depression symptoms, suggesting a new transdiagnostic treatment target. Social-environmental stressors, such as remote learning and contact with fewer friends, may exacerbate the connection between reward deficits and social anxiety-depression co-occurrence and serve as areas for intervention.