A Polymorphism in the Serotonin Transporter Gene Moderates Cardiovascular Reactivity to Psychosocial Stress

Objective: To examine whether a polymorphism (5-HTTLPR: serotonin transporter linked polymorphic region) in the promoter of the serotonin transporter gene (SLC6A4) moderates cardiovascular reactivity to social threat. Methods: Psychologically healthy young adults delivered a speech and performed mental arithmetic in one of three conditions: a) an evaluative audience condition that gave disapproving and negative nonverbal social signals (n = 59); b) an evaluative audience condition that provided supportive social signals (n = 60); or c) a no audience condition (n = 65). Heart rate (HR) and systolic and diastolic blood pressures (DBP) were measured before, during, and after the stress tasks to assess cardiovascular reactivity and recovery. Results: In the negative audience condition, there was a significant association between the 5-HTTLPR and systolic blood pressure, DBP, and HR reactivity. Individuals with the short/short genotype showed the greatest reactivity. The DBP and HR reactivity of short/short individuals in the negative audience condition was also greater than that of individuals with the short/short genotype in the no audience condition. These associations of the 5-HTLPR with HR reactivity were moderated by gender, being limited to females. With respect to cardiovascular recovery, short/short individuals in the negative audience condition exhibited impaired DBP recovery relative to other genotypes in the same condition, as well as short/short individuals in the no audience condition. Conclusions: The 5-HTTLPR moderates cardiovascular reactivity to stress in a threatening evaluative social context, which suggests that the serotonin system may be involved in the processes by which stressful, conflict-ridden social environments affect risk for cardiovascular-related health outcomes.