Doctor of Philosophy (PhD)



Document Type



Recent research investigating social risk factors of depression has found evidence for a social contagion effect. The research comes from a surge in popularity of using social network analyses to examine the spread of various health outcomes such as obesity, smoking, substance use, and sleep. Although the finding of depressive contagion represents a significant contribution to the literature on the social etiology of depression, this is only the first step in providing meaningful research useful for the practical application of curbing the growing rates of depression especially among adolescents. Rather than simply acknowledging the existence of contagion effects, researchers must begin to answer the question of whether certain individuals or environments are more susceptible to the effects of depressive contagion. As a result, this dissertation applies a differential susceptibility model to examine three moderators of depressive contagion: social network structure, racial/ethnic identity, and genotypic variation in the serotonin transporter (SLC6A4) gene. The research in this dissertation uses data from the National Longitudinal Study of Adolescent Health (Add Health). First, the results reveal that adolescents who are popular and/or embedded in dense peer networks are more susceptible to depressive contagion. Additionally, depressive contagion is more salient in schools characterized by dense social networks and high reciprocity in social ties. Second, racial homophily plays an important role in the effect of depressive contagion. Adolescents embedded in racially homophilous peer networks are more susceptible to depressive contagion. Further analysis shows that this effect applies primarily for Asians and Hispanics. Finally, results indicate a significant gene-environment interaction (GxE) effect between a polymorphism in the serotonin transporter system (5-HTTLPR) and depressive contagion. Adolescents carrying one or two short alleles in the 5-HTTLPR are more susceptible to depressive contagion.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Blanchard, Troy C.



Included in

Sociology Commons