An Integrated Immuno-Reward Model of Adolescent Depression: Theory, Evidence, and Implications

Adolescence is an "age of risk" for the emergence of depression. Despite its prevalence and public health significance, there are major unanswered questions regarding the mechanisms contributing to depression's etiology and surge in adolescence. Separate lines of research have investigated the roles of inflammation and low reward responsiveness in depression and recent evidence suggests bidirectional associations between inflammation and reward responsiveness. In this article, we review this evidence, present an integrated immuno-reward model of adolescent depression, specifically, motivational and somatic symptoms of depression, and discuss the role of stress and early adversity in amplifying immune-reward interactions. We end with implications of the immuno-reward model for future research, early identification of at-risk adolescents, intervention, and public health policy.