Stress reactivity in salivary cortisol and electrocardiogram in adolescents: Investigating sleep disturbances and insomnia

This study examined the role of sleep disturbances and insomnia in the context of stress reactivity in adolescence. One-hundred and thirty-five 11-18 year olds (M_age  = 14.2 years, SD = 1.9, 52% female) completed the Trier Social Stress Test for Children. Salivary cortisol and subjective stress ratings were collected at six time points, and heart rate as well as heart rate variability were measured pre-, during and post-stress induction. Additionally, sleep disturbances and insomnia diagnosis were assessed by a self-report questionnaire and a sleep interview. Robust mixed models investigated if adolescents with compared with adolescents without (a) sleep disturbances and (b) insomnia differ regarding cortisol, heart rate, heart rate variability and psychological stress reactivity considering gender effects. The results indicated that boys with high sleep disturbances showed higher cortisol activity compared with boys with low sleep disturbances, B = 0.88, p < 0.05. Moreover, in boys with insomnia, heart rate and alpha 1 significantly differ less than in boys without insomnia. These findings support the notion of sex differences regarding the association between poor sleep and increased activity of the hypothalamic-pituitary-adrenal axis, and a less adaptable autonomic nervous system in boys in response to an experimental social stress task.

The effect of sleep on the salivary cortisol response to acute stressors: a review and suggestions

There have been steadily increasing studies on the relationship between sleep and stress. However, the findings regarding the effects of sleep on the acute stress response have been inconsistent. Elevated, blunted, or unchanged salivary cortisol stress response have been reported. Therefore, this study conducted a systematic review of previous studies to provide a comprehensive summary of the factors that influence the effects of sleep on the salivary cortisol stress response. We conducted a comprehensive electronic literature search in PubMed, PsycINFO, PsycARTICLES, Web of Science, MEDLINE, and EMBASE for human studies published in English (up to June 2019). Finally, 17 articles with participants aged 6.4-72 years were included in this review. We assessed the following factors: designing factors (sleep measurement, stress induction, cortisol sampling period, and time intervals between sleep measurement and the acute stress task), analyzing factors (cortisol analysis), and participants' characteristics (age, sex, and background stress levels); subsequently, we explained conflicting findings across the current literature. Further, we provide study design, analysis, and report suggestions for optimal assessment of the effects of sleep on the acute stress response. This summary of influencing factors and suggestions for future studies could help elucidate the impact of sleep on stress and advance the field.

Responses to academic stress mediate the association between sleep difficulties and depressive/anxiety symptoms in Chinese adolescents

OBJECTIVE

Sleep difficulties are pervasive in Chinese adolescents, which exert aversive influence on their emotional health. However, the underlying mechanisms of this effect remain unclear. This study addressed whether stress responses mediate the concurrent and prospective relationship between sleep difficulties and depressive/anxiety symptoms in Chinese adolescents.

METHOD

17,946 adolescents (14-18 years-old) were administrated the Pittsburgh Sleep Quality Index, the Center for Epidemiologic Studies Depression Scale, Revised Children's Manifest Anxiety Scale and the Responses to Stress Questionnaire. Further, 710 of them finished the one-year follow-up assessments. Structural equation models were conducted to determine the concurrent and prospective mediation effects of stress responses and the moderated effect of gender and age.

RESULTS

Involuntary engagement and disengagement responses, as well as engagement coping, significantly mediated the cross-sectional relationship between sleep difficulties and depressive/anxiety symptoms. Moreover, sleep difficulties at baseline predicted enhanced involuntary engagement responses but reduced the use of engagement coping strategies one year later, resulting in an elevated level of depressive/anxiety symptoms. Finally, females and younger adolescents with greater sleep difficulties were more likely to generate maladaptive stress responses.

LIMITATIONS

First, sleep difficulties were only measured using self-reported approaches. Second, potential confounding variables (e.g., socioeconomic status) were not adjusted for. Third, our study only focused on typically-developing youth samples rather than clinical samples.

CONCLUSIONS

Our findings highlight the important role of stress responses in the relationship between sleep difficulties and depressive/anxiety symptoms. The findings might also shed some light on the psychological intervention of sleep difficulties and mood disorder in adolescent populations.