Physiological responses to acute psychosocial stress in adolescents with insomnia

Abstract Introduction Insomnia often develops during adolescence, with girls being at greater risk than boys. Alterations in response to psychosocial stress have been linked to the etiology of the disorder, but it remains unclear whether the reactivity of the major stress systems (hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS)) in response to stress is altered in adolescents with insomnia. Methods Forty-seven post-pubertal adolescents (age range: 16-20 years, 28 female) with (N=16; insomnia group) and without (N=31; control group) insomnia symptomatology underwent two randomized nights of polysomnographic (PSG) laboratory recordings. Participants underwent an experimental pre-bedtime stress anticipation protocol (stress night) and a control night during which they engaged in neutral activities before bedtime. The morning after the stress night, participants underwent the Trier Social Stress Test (TSST), a standardized protocol that requires participants to complete verbal and arithmetic tasks in front of observers. On both nights, heart rate (HR) was measured across the night and cortisol was collected upon awakening and 30 minutes later to calculate cortisol awakening responses (CAR). Stress perception, salivary cortisol (HPA activity), and HR were measured during the TSST. Results There were no differences in nocturnal HR recovery or in the CAR on the stress night compared with the control night in either group. Morning pre-TSST stress levels did not differ between groups. Both groups exhibited significant increases in HR in response to the TSST (p< 0.05). HR was higher in girls compared to boys in the control group at baseline (p< 0.05). Potential group differences in HPA responses to the TSST were inconclusive due to the apparent confounding effect of the CAR on cortisol responses to stress: many participants did not show a cortisol response to the task and larger CARs were associated with an attenuated cortisol response. Conclusion There were no significant differences in HR responses to anticipation of experimental stress during the night or in response to the morning TSST between adolescents with and without insomnia. Further work is needed to examine whether altered responses to stress may emerge if insomnia becomes chronic. Support (if any) This study was supported by the National Heart, Lung and Blood Institute (NHLBI) grant R01HL139652(MdZ).