Reward Deficits in Comorbid 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) explained 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 explained 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, exploratory analyses suggested 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 comorbid social anxiety-depression symptoms. This is the first study to report the strong role of boredom in this comorbidity, 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 comorbidity and serve as areas for intervention.