Stress, hypothalamic pituitary adrenal axis activity and autonomic nervous system function in adolescents with insomnia.

Introduction: Abnormal stress responses have been linked to the etiology of insomnia. We investigated the relationship between insomnia, stress, hypothalamic-pituitary-adrenal (HPA) axis activity, and autonomic nervous system (ANS) function in adolescence.

Methods: Forty-seven post-pubertal adolescents (16-20 years old, 28 female) with (N = 16; insomnia group) and without (N = 31; control group) DSM-5 insomnia symptoms were assessed for stress levels and stress reactivity and underwent a standardized stress protocol (Trier Social Stress Test (TSST)), after an overnight laboratory stay. Cortisol was measured upon awakening and 30-minutes later to calculate the cortisol awakening response (CAR). During the TSST, perceived stress, salivary cortisol (HPA activity), heart rate (HR) and blood pressure (BP) measures were collected.

Results: Participants in the insomnia group reported more stress from school performance and work overload, with insomnia girls experiencing more stress from peer pressure and future uncertainty than control girls (p < 0.05). No group differences were detected in the CAR and pre-TSST stress levels. All participants showed significant increases in perceived stress (~19 %), HR (~33 %), systolic (~13 %), and diastolic (~15 %) BP in response to the TSST (p < 0.05). Overall HR stress response did not differ between groups, but was lower in boys with insomnia than in girls with insomnia (p < 0.05). Cortisol stress responses were inconclusive, possibly due to a masking effect of CAR, as the task was performed shortly after awakening and larger CARs were associated with blunted cortisol stress responses.

Discussion: Results mostly show no group difference in physiological stress responses, although some interaction effects suggest a potential sex by insomnia interaction. Larger samples are needed to understand the physiological disturbances of insomnia in adolescence.