Understanding the social determinants of depression has remained a primary concern in the mental health literature for decades. Investigation into the topic has been productive, yielding a number of robust empirical findings and organizing theoretical frameworks. Thus, social scientists have made substantial progress in elucidating how social factors including stressful events, social support and socio-economic status influence depression over the life course. However, it is also clear that there are considerable individual differences in the impact of social factors, with some individuals showing greater vulnerability than others. This fact suggests that much of the variance in depression is due to interactions between social factors and personal characteristics not typically examined in social science research. This dissertation elaborates this line of reasoning, investigating social moderation of the influence of five neurotransmitter candidate genes and physical attractiveness on depression using data from the National Longitudinal Study of Adolescent Health. In the first empirical chapter, the direct and interactive influences of candidate genes and various dimensions of social environmental risk on depression are examined. Using false discovery rate (FDR) methods to account for multiple testing, evidence suggests possible interactions between the MAOA VNTR promoter polymorphism, particularly the 2 repeat and 3.5/4 repeat variants, and social support among females. In the second empirical chapter, temporal variation in the influence of neurotransmitter candidate genes across early life is examined. Again using FDR methods to account for multiple testing, results indicate temporal variation in the effects of the DRD4 dopamine receptor gene (5 repeat variant) for the full sample, and the MAOA VNTR promoter polymorphism (3.5 repeat) among males. The final substantive chapter examines the depressogenic influence of another source of individual differences rarely considered by social scientists--physical attractiveness. Results indicate that attractiveness becomes increasingly influential on depression as individuals age through adolescence and young adulthood, and that less attractive individuals are more resilient to the effects of eventful stress than their more attractive counterparts. Overall, this research demonstrates that, in addition to their main effects on depression, social factors represent important moderators of the influence of genetic variation and physical attractiveness
