Gender moderates diurnal cortisol in relation to trauma and PTSD symptoms: A study in Sri Lankan adolescents

Trauma exposure and posttraumatic stress disorder (PTSD) have been linked to aspects of diurnal cortisol secretion in adolescents, but little is known about gender differences in these associations. A school-based sample of Sri Lankan adolescents aged 13-16 years took part in this study 4.5 years after the 2004 tsunami had impacted many of their lives to varying degrees. Saliva samples were obtained 4 times a day for 3 days in 84 participants, who also completed measures of lifetime trauma, current stressors, and posttraumatic stress symptoms (PTSS). We used multilevel regression to estimate effects of trauma exposure and symptoms on cortisol level, diurnal slope, and awakening response (CAR). Results indicated higher cortisol in girls and older adolescents. Although trauma, PTSS, and recent PTSD had non-significant main effects, these three variables interacted with gender, with higher cortisol in girls than in similarly traumatized or symptomatic boys. Co-occurrence of internalizing symptoms and PTSS was also associated with higher cortisol. The 28 adolescents with recent PTSD displayed flatter diurnal slopes, reflecting relatively low morning cortisol. Among the 56 trauma-exposed participants, negative trauma appraisals were associated with higher cortisol. Girls were more likely than boys to display elevated cortisol in relation to re-experiencing and hyperarousal symptoms. In contrast to significant findings for cortisol level and diurnal slope, the CAR showed no association with either trauma or PTSS, irrespective of gender. Findings, viewed in light of normative gender differences in HPA activity during adolescence, can contribute to understanding heightened female vulnerability to posttraumatic stress disorder.