Does Social Support Moderate the Link Between Chronic Peer Victimization in School and Cortisol Secretion?

• In Event: Peer Relations as a Risk Factor for Negative Developmental Outcomes: Addressing High Priority Understudied Areas

Abstract

Introduction. Peer victimization is believed to negatively affect victims’ mental and physical health through changes in neurophysiological stress systems, notably the functioning of the hypothalamic-pituitary-adrenal (HPA) axis. The most frequently studied biomarker in this regard is cortisol. Several studies have linked peer victimization with altered cortisol secretions (for a review, see Kliewer et al., 2019), even when controlling for genetic influences on cortisol secretion (Brendgen et al., 2017; Ouellet-Morin et al., 2011). Findings are inconsistent, however, with some studies showing an association between peer victimization and blunted cortisol secretion but others reporting the reverse or no association. While methodological differences may be partly responsible for these inconsistencies, another possibility is the presence of moderating factors—notably the chronicity of victimization experiences or the level of social support. Indeed, while exposure to an acute, but temporary stressor may lead to cortisol increases, consistently high cortisol levels due to chronic stress exposure may ‘desensitize’ the body and eventually lead to a counter-regulatory state of cortisol hypo-secretion when faced with stress (Miller et al., 2007). However, social support may buffer against the physiological effects of stressful experiences such as peer victimization (Hostinar & Gunnar, 2015). Hypotheses. Using a genetically informed design based on twins, the present study tested whether chronic peer victimization in adolescence (ages 12 to 16) predicts blunted cortisol secretion later on (age 19) and whether this association is mitigated by social support during adolescence. These associations were expected even when controlling for genetic influences on cortisol as well as current victimization experiences at age 19. Study Population. Participants were a longitudinal sample of 148 Monozygotic and 227 Dizygotic twin pairs (i.e., 750 individuals, 56% girls). Method. Participants self-reported on their peer victimization and social support from the mother, father, and best friend from ages 12 through 17. They also reported on victimization experiences in college, at work or in romantic relationships at age 19. In addition, participants provided a hair sample for cortisol extraction at age 19. Hair cortisol (HC) is more stable and less malleable by situational factors than salivary cortisol and reflects cumulative cortisol secretion over the previous three months (Stalder et al., 2012). Results. Growth mixture modeling identified three victimization trajectories from ages 12 through 17: low (34%), moderate (55%), and high (11%) (Figure 1). Biometric modeling showed that genetic factors explained 33% of HC levels in girls and 40% in boys. As expected, controlling for genetic influences and concurrent victimization experiences at age 19, a consistently high trajectory of peer victimization at ages 12 through 16 years predicted lower HC levels compared to a consistently low trajectory, but only when friend’s support was low (b = -.34, 95%CI -.68/-.01; region of significance = friend’s support at -1 SD or lower). No other main or interaction effects emerged. No sex moderation was found. These results suggest that consistently high peer victimization may contribute to “wear‐and‐tear” on the body by inducing cortisol hypo-secretion, but that this process may be counteracted by at least some level of social support.

Authors

• Mara Brendgen, L'Université du Québec à Montréal (UQAM)
  Presenting Author

• Isabelle Ouellet-Morin, Université de Montréal

• Christina Cantave

• Frank Vitaro, Université de Montréal

• Ginette Dionne, Universite Laval

• Michel Boivin, Universite Laval