Abstract
The current study examined whether a dopamine receptor gene (DRD2) TaqIA polymorphism and a serotonin transporter polymorphism (5HTTLPR) moderate the effects of stressful life events on depression, and whether these interaction effects vary by type of stressor. In addition, individuals' responses to stressful life circumstances might vary by genotype, gender, and/or race. A sample of 2,023 participants from waves II and III of the National Longitudinal Study of Adolescent Health (Add Health) submitted buccal cells for genotyping and completed self-report surveys that inquired about their victimization and depressive symptoms. Results showed that the DRD2 TaqI polymorphism interacts with specific types of stressful life circumstances, and these results vary across gender and race subgroups. More specifically, the DRD2 polymorphism interacts with witnessed violence to predict higher levels of depressive symptoms among African American females. The DRD2 polymorphism does not moderate the effects of stressful life circumstances on depressive symptoms for White females, White males, or African American males. 5HTTLPR does not moderate the effects of stressful life circumstances on depression in the current study for any of the gender-race subgroups. These findings suggested that the interactive effects of the DRD2 TaqI polymorphism and stressful life circumstances on depressive symptoms might vary by type of stressor, and by ethnicity and gender. Copyright (C) 2009 John Wiley & Sons, Ltd.