Chronic family stress interacts with 5-HTTLPR to predict prospective depressive symptoms among youth.

Background: Previous research, predominantly with adults, has shown that the serotonin transporter gene (5-HTTLPR) interacts with stress (G × E) to predict depressive symptoms; however, few G × E studies have been conducted with youth using rigorous methods, particularly a prospective design and contextual interview to assess stress. This study examined the interaction between 5-HTTLPR and stress, both chronic and episodic, to predict longitudinal change in depressive symptoms among children and adolescents.

Methods: A general community sample of youth (N = 200; 57% girls; mean age: 12.09 years old) was genotyped for 5-HTTLPR (rs 25531) at baseline. They were interviewed via contextual stress procedures to ascertain chronic family stress and episodic stressors and completed depressive symptoms questionnaires at baseline and 6 months later.

Results: A significant G × E showed that chronic family stress predicted prospective increases in depressive symptoms over 6 months among youth possessing the high-risk S allele. This G × E was not found for episodic stressors occurring in the last 6 months. There was no moderation by sex or pubertal status.

Conclusions: These findings advance knowledge on G × E effects in depression among youth. This is the first study to show that chronic family stress, but not episodic stressors, when ascertained by rigorous stress interview, interacts with 5-HTTLPR to prospectively predict depressive symptoms among children and adolescents.