Linking post-stressor interpersonal processes in adolescent girls’ close friendships with acute HPA stress responses

Introduction: For adolescent girls, close friendships may facilitate stress management and mitigate risk for internalizing psychopathology. However, little is known about how friendship processes may buffer (or potentially exacerbate) acute psychobiological responses to interpersonal stressors in ways that affect risk. Methods: In a sample of 220 girls (ages 12-17 years) with a history of internalizing symptoms, this study investigated friendship dynamics following the Trier Social Stress Test (TSST) to evaluate associations between post-stressor friendship behaviors (expressions of vulnerability by the stressed teen; support offered by their close friend) and hypothalamic-pituitary-adrenal (HPA) axis stress responses. Results: Multilevel regression modeling revealed that girls who displayed more pronounced cortisol reactivity expressed greater vulnerability to, and received greater support from, their close friend. Expressed vulnerability was associated with more efficient cortisol recovery. Close friend support was not significantly associated with cortisol recovery, nor did it influence the connection between expressed vulnerability and cortisol recovery. Conclusions: Findings suggest that HPA reactivity may prompt expressions of vulnerability to girls' close friends, and in this context, promote more efficient HPA recovery. Findings highlight the role friendship dynamics may play in HPA-related risk for internalizing symptoms and point to expressed vulnerability in adolescent girls' close friendships as a potential consideration for interpersonally-centered therapeutic approaches.