Dissecting the impact of sleep and stress on the cortisol awakening response in young adults

Relationship of sleep with diurnal cortisol rhythm considering sleep measurement and cortisol sampling schemes

Information on the relationships between the previous night's sleep and the next-day diurnal cortisol rhythm is inconsistent due to confounding factors such as sleep measurements (trait/state sleep and objective/subjective sleep) and cortisol sampling schemes. Therefore, this study aimed to investigate these relationships, considering the confounding factors. College students (n = 79) wore actigraphy for 3 days to undergo an evaluation of previous night-time sleep objectively and reported their subjective sleep parameters in a sleep diary. In addition, participants provided six salivary cortisol samples daily. Furthermore, six cortisol sampling schemes were created to reflect diurnal cortisol rhythms, and two different methods were used to calculate the index of diurnal cortisol slope (DCS). A multilevel model was created to examine the impact of both trait and state sleep on next-day diurnal cortisol rhythm. The results revealed that higher objective state sleep efficiency and longer objective state total sleep time were associated with a higher cortisol awakening response (CAR). Moreover, higher objective trait sleep efficiency and longer objective trait total sleep time were associated with higher waking cortisol levels and steeper DCS. In addition, a minimum of four saliva samples were required at different time points, including upon waking, 30 min after waking, 1 h after waking, and at bedtime, to explore the relationship of sleep efficiency/total sleep time with waking cortisol, CAR, and DCS. Furthermore, the index of the peak-to-bed slope was appropriately employed to examine the relationship between sleep efficiency and DCS, whereas the wake-to-bed slope was effective for examining the relationship between total sleep time and DCS. In summary, this study clarified the relationship between sleep and next-day diurnal cortisol rhythm and suggested a cost-effective cortisol sampling schedule and calculation methods.

The Development of Stress Reactivity and Regulation in Children and Adolescents

Adversity experienced in early life can have detrimental effects on physical and mental health. One pathway in which these effects occur is through the hypothalamic-pituitary-adrenal (HPA) axis, a key physiological stress-mediating system. In this review, we discuss the theoretical perspectives that guide stress reactivity and regulation research, the anatomy and physiology of the axis, developmental changes in the axis and its regulation, brain systems regulating stress, the role of genetic and epigenetics variation in axis development, sensitive periods in stress system calibration, the social regulation of stress (i.e., social buffering), and emerging research areas in the study of stress physiology and development. Understanding the development of stress reactivity and regulation is crucial for uncovering how early adverse experiences influence mental and physical health.

Sex differences in cortisol levels in depression: A systematic review and meta-analysis

Higher prevalence of depression in females might be associated with sex-specific cortisol levels. Evidence exists that cortisol levels differ between healthy females and males, however a sex-specific association in depression has not been systematically assessed. Thus, the current study quantifies the existing literature on different cortisol parameters, i.e., basal cortisol, hair cortisol, cortisol awakening response (CAR), and cortisol stress reactivity comparing depressed females and males as well as sex-specific comparisons with healthy controls. Following an extensive literature research, fifty original articles were included. Depressed females had significantly higher hair cortisol, higher CAR, and lower cortisol stress reactivity compared to depressed males. In comparison with sex-matched controls, female patients had significantly higher evening basal cortisol, higher CAR and lower cortisol stress reactivity, and male patients had significantly higher general, morning and evening basal cortisol. Overall, sex as a fundamental driver of cortisol levels in depression needs to be taken into account.

Stress before conception and during pregnancy and maternal cortisol during pregnancy: A scoping review

BACKGROUND

Stress before conception and during pregnancy is associated with less favorable maternal and child health. Alterations in prenatal cortisol levels may serve as a central biological pathway linking stress to adverse maternal and child health. Research examining associations between maternal stress from childhood through pregnancy and prenatal cortisol has not been comprehensively reviewed.

METHOD

The current scoping review of 48 papers synthesizes studies reporting on associations between stress before conception and during pregnancy with maternal cortisol in pregnancy. Eligible studies measured childhood, the proximal preconception period, pregnancy, or lifetime stress based on stress exposures or appraisals and measured cortisol in saliva or hair during pregnancy.

RESULTS

Higher maternal childhood stress was associated with higher cortisol awakening responses and alterations in typical pregnancy-specific changes in diurnal cortisol patterns across studies. In contrast, most studies of preconception and prenatal stress reported null associations with cortisol and those reporting significant effects were inconsistent in direction. A few studies found that the associations between stress and cortisol during pregnancy varied as a function of several moderators including social support and environmental pollution.

CONCLUSIONS

Although many studies have evaluated effects of maternal stress on prenatal cortisol, this scoping review is the first to synthesize existing literature on this topic. The association between stress before conception and during pregnancy and prenatal cortisol may depend on the developmental timing of stress and several moderators. Maternal childhood stress was more consistently associated with prenatal cortisol than proximal preconception or pregnancy stress. We discuss methodological and analytic factors that may contribute to mixed findings.

The impact of caregiving for children with chronic conditions on the HPA axis: A scoping review

Caregiving has been robustly linked to caregiver health through the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in the context of caregiving for an adult with a chronic illness. However, little research examines the physiological impact of caregiving for a child with a chronic illness despite high burden and unique stressors. In this review, we explore the links of caregiving for a child with a congenital, chromosomal, or genetic disorder to the regulation or dysregulation of the HPA axis. A search was conducted in PubMed, Embase, and the Web of Science and 15 studies met inclusion criteria. Overall, there were inconsistent links of caregiving to HPA axis functioning, perhaps due to the heterogeneity across disease contexts, study designs, and biomarker measurement. Future research should standardize measurement and study designs, increase participant diversity, and examine moderators of the links of caregiving to the HPA axis.

Hugs and Cortisol Awakening Response the Next Day: An Ecological Momentary Assessment Study

Previous research suggests that affectionate touch such as hugs might downregulate stress systems such as the hypothalamic pituitary adrenal (HPA) axis. However, the current literature lacks in generalizability beyond the laboratory setting and outside the context of romantic relationships. The cortisol awakening response (CAR) is a measure of the HPA axis and is responsive to daily fluctuations in stress and social information. However, associations between affectionate touch and the CAR have never been assessed. This study used ecological momentary assessment (EMA) to measure daily hugging behaviors in 104 first-year college students and salivary cortisol to assess the CAR. Participants who reported more daily hugs in their social interactions had significantly smaller CARs the next morning compared to days they reported fewer hugs. This study contributes to the literature on social interactions and stress responsive systems and emphasizes the importance of assessing affectionate touch behaviors such as hugs that can be exchanged outside the context of romantic relationships.

Mild to Moderate Sleep Restriction Does Not Affect the Cortisol Awakening Response in Healthy Adult Males

The cortisol awakening response (CAR) is a distinct rise in cortisol that occurs upon awakening that is thought to contribute to arousal, energy boosting, and anticipation. There is some evidence to suggest that inadequate sleep may alter the CAR, but the relationship between sleep duration and CAR has not been systematically examined. Healthy males (n = 111; age: 23.0 ± 3.6 yrs) spent 10 consecutive days/nights in a sleep laboratory. After a baseline night (9 h time in bed), participants spent either 5 h (n = 19), 6 h (n = 23), 7 h (n = 16), 8 h (n = 27), or 9 h (n = 26) in bed for seven nights, followed by a 9 h recovery sleep. The saliva samples for cortisol assay were collected at 08:00 h, 08:30 h and 08:45 h at baseline, on experimental days 2 and 5 and on the recovery day. The primary dependent variables were the cortisol concentration at awakening (08:00 h) and the cortisol area under the curve (AUC). There was no effect of time in bed on either the cortisol concentration at awakening or cortisol AUC. In all the time in bed conditions, the cortisol AUC tended to be higher at baseline and lower on experimental day 5. Five consecutive nights of mild to moderate sleep restriction does not appear to affect the CAR in healthy male adults.

Race moderates the association between adult attachment avoidance and the cortisol awakening response among young sexual minority men

Adult attachment, or the ways in which individuals develop and maintain trusting and loving relationships with peers and romantic partners, has been demonstrated to influence hypothalamic-pituitary-adrenal (HPA) axis functioning among young sexual minority men (YSMM). Theory and preliminary evidence suggest that differences in the lived experiences of White and Black sexual minority young adults may influence the way in which adult attachment influences the HPA-axis functioning. We sought to further this field of inquiry by examining if race moderates the association between adult attachment insecurity (i.e., avoidance and anxiety) and HPA-axis functioning among YSMM. Sixty-three YSMM participated in a 5-day daily diary study in which they completed a baseline survey to assess adult attachment orientation and provided saliva samples 4 times per day over a 5-day period in order to measure cortisol across the day. Three-level hierarchical linear modeling was used to examine the association between adult attachment, the cortisol awakening response (CAR), diurnal cortisol, and the moderating effect of race. We found no main effect of attachment anxiety or avoidance on HPA-axis functioning. However, we found that race moderated the association between adult attachment avoidance and the CAR such that Black YSMM with higher attachment avoidance had a lower CAR as compared to White YSMM. Results suggest that there may be key differences between White and Black YSMM men's lived experiences that should be explored in future research.

Diurnal Cortisol in Left-Behind Adolescents: Relations to Negative Family Expressiveness and Internalizing Problems

Despite the accumulating evidence for increased risks for behavioral problems in left-behind adolescents in China, little research has explored their HPA axis functioning, which is hypothesized to play a central role in the association between early adversity and health. In the present study, we designed a longitudinal study to examine HPA axis function in left-behind adolescents and its mediating role in the association between family emotional expressiveness and internalizing problems. Participants were 81 adolescents (44 female; 37 male) aged 11-16 years. Salivary cortisol samples were collected six times a day for two consecutive days on regular school days. Negative family expressiveness (NFE) and internalizing problems were measured using self-report questionnaires. The results showed that NFE was negatively associated with diurnal cortisol, and diurnal cortisol was negatively associated with internalizing problems. Further analysis showed that diurnal cortisol secretion measured by AUC (area under the curve) mediated the association between NFE and internalizing problems. Our findings extended the existing literature about left-behind children via a psychoneuroendocrinological perspective, documenting the negative consequences of the family environment for youth health and development.

School commute time, chronotype, and altered HPA axis functioning during adolescence

Hypothalamic pituitary adrenal gland (HPA) axis functioning has been linked with daily demands during adolescence. A ubiquitous, yet understudied daily demand in the lives of youth is the commute to school, which may be associated with the diurnal rhythm of cortisol as demonstrated in prior research among adults. The current study hypothesized that longer school commute times would be associated with altered HPA axis functioning as demonstrated by a heightened cortisol awakening response (CAR) and flatter diurnal slope. Additionally, given that the HPA axis follows a diurnal rhythm and adolescence is marked by changes in the circadian rhythm, adolescents with a more evening chronotype were hypothesized to evince even more altered HPA axis functioning in the face of long school commute times. A total of 269 adolescents (M = 16.38 years, SD = 0.74) provided saliva samples at wake, 15-min. post-wake, and 30-min. post-wake for the calculation of CAR and at dinnertime and bedtime for the calculation of diurnal slope, completed up to 8 nights of sleep actigraphy, and self-reported school commute time. Results suggest that more evening chronotype youth with longer school commute times evince a higher CAR, but not an altered diurnal slope. The present findings may have implications for adolescent mental health as higher CAR has been associated poor mental health and heightened stress.

Constructs of poor sleep quality in adolescents: associated factors

This study aims to evaluate factors associated with sleep quality (overall and by domains) in adolescents. A cross-sectional study. This study was conducted with 1,296 first-year high school students from public schools in the Northern Region of the State of Pernambuco, Brazil. Demographic, socioeconomic, and behavioral data were obtained with a questionnaire. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI) Body mass index (BMI) was calculated based on the ratio of weight and height squared. Multilevel linear and logistic regressions evaluated factors associated with sleep quality. We observed 53% of adolescents reported poor sleep quality. Adolescents at higher risk of clinical depression were 3.45 times more likely to have poor sleep quality (95%CI: 2.04; 5.81), and each additional unit in the social anxiety score presented 1.03 (95%CI: 1.01; 1.05) higher odds of adolescents having poor sleep quality. Adolescents with depressive symptoms had higher sleep latency, greater sleep disturbance, and greater daytime sleep dysfunction. Social anxiety was associated with sleep latency, sleep disturbance, and daytime sleep dysfunction. Higher risk of clinical depression was associated with all domains related to sleep quality. Negative health perception was associated with sleep disturbance, and physical inactivity was associated with daytime sleep dysfunction. Social anxiety and especially higher risk of clinical depression were determinants of poor sleep quality. Changes in sleep latency, sleep disturbance and daytime sleep dysfunction seems to be relevant to poor sleep quality.

Examining the same-day relationship between morning cortisol after awakening, perceived stress in the morning, and physical activity in youth

Most children in the United States currently do not meet physical activity (PA) guidelines, and perceived stress is a known barrier against PA. However, most studies have solely focused on the between-subject (BS) association of stress and PA, whereas the within-subject (WS) relationship remains under-studied in children. This limits our understanding of day-level psychosocial factors that influence children's PA engagement. This study assessed the same-day associations of the Morning Cortisol after Awakening (MCA) and morning perceived stress with moderate-to-vigorous physical activity (MVPA) in children using Ecological Momentary Assessment (EMA) methodologies. The analytic sample consisted of 143 children from Los Angeles in the Mothers and Their Children's Health (MATCH) study. Children collected four saliva samples and wore accelerometers to assess MVPA minutes across four days (two weekdays and two weekend days) during each data collection wave. On weekend days, they also answered a mobile phone EMA survey on perceived stress within 1 h of awakening. Data from four assessment waves, each approximately six months apart, were combined and analyzed cross-sectionally. Multilevel modeling, which adjusts for the nested data structure, was used to test the same-day associations of MCA and weekend morning perceived stress with MVPA. On weekend days when morning perceived stress was higher than usual, participants engaged in more MVPA on the same day (β = 0.79, SE = 0.32, p = 0.02), but no association was found between MCA and MVPA. These findings elucidate same-day factors that predict MVPA in children and inform future WS studies on stress and PA.HighlightIt is unknown how stress influences children's daily activity levels. We tested if two types of stress (self-reported and saliva-measured) are related to children's daily activity. We found that self-reported stress is associated with physical activity, but saliva-measured stress is not.

The impact of prior day sleep and physical activity on the cortisol awakening response

The cortisol awakening response (CAR) describes the increase in cortisol within the first 30-60 min after waking from nocturnal sleep, and is a common biomarker used within psychoneuroendocrinology, but the effect of sleep on the CAR is currently unclear. A previous study suggested that reported discrepancies may be due to other lifestyle behaviors such as physical activity; given the role of the CAR in energy regulation and preparation for the day, it is theoretically plausible that activity level would influence the CAR. However, no study has yet utilized objective monitoring of day-to-day sleep and physical activity to investigate potential effects on the CAR. This study aimed to test the hypotheses that either sleep duration or sleep quality would interact with the prior 24 h' physical activity to predict the CAR on the following morning. Salivary samples were collected from 85 young adults (mean = 19.1 years, SD = 1.89) immediately after waking from nocturnal sleep and again 30 min after waking; two complete and consecutive days were used. Participants wore accelerometers (ActiGraph, wGT3X-BT) throughout this phase of a larger study, which provided objective measures of sleep duration, number of awakenings, and amount of physical activity. Mixed-effects models with post-hoc regions of significance decompositions tested the hypothesized interaction effects. Results demonstrated a significant interaction between prior day sleep duration and physical activity predicting the next day CAR, wherein short sleep duration and high levels of physical activity resulted in an augmented CAR. Although more sleep clearly predicted a smaller next day CAR in main effect, this study provides additional support that sleep duration effects are also moderated by prior day physical activity. Both behavioral factors should be considered when assessing the CAR and the association between the CAR other psychoneuroendocrine outcomes.

Effects of Overtraining Status on the Cortisol Awakening Response-Endocrine and Metabolic Responses on Overtraining Syndrome (EROS-CAR)

The cortisol awakening response (CAR) is a distinct component of the circadian cortisol profile and has promise as a biomarker for the monitoring of athlete readiness and training status. Although some studies have suggested the CAR may be affected by the development of overtraining syndrome (OTS), this has yet to be systematically investigated.

PURPOSE

To compare the CAR and diurnal cortisol slope between athletes diagnosed with OTS, healthy athletes, and sedentary controls.

METHODS

This study was a secondary analysis of data from the Endocrine and Metabolic Responses on Overtraining study. Male participants were recruited to either OTS, healthy athlete, or sedentary control groups. The participants produced saliva samples immediately after waking (S1), 30 minutes after waking (S2), at 16:00 hours, and at 23:00 hours. Salivary cortisol concentration was determined by an electrochemiluminescence assay. Mixed-effects models were used to assess the conditional effect of group (sedentary controls, OTS, and healthy athletes) on the change in cortisol over time. Separate models were fit for the awakening samples (S1 and S2) and for the diurnal slope (linear change across S1, 16:00 h, and 23:00 h).

RESULTS

The models demonstrated significant time-by-group interaction for OTS for the 2 cortisol concentrations collected during the awakening period (β = -9.33, P < .001), but not for the diurnal cortisol slope (β = 0.02, P = .80).

CONCLUSIONS

These results suggest the CAR may be associated with OTS and should be considered within a panel of biomarkers. Further research is necessary to determine whether alterations in the CAR may precede the diagnosis of OTS.

Effects of nightmares on the cortisol awakening response: An ambulatory assessment pilot study

Previous studies have reported an association between sleep-related factors such as sleep duration, sleep quality and time of awakening with the cortisol awakening response (CAR). Preliminary evidence suggests that frequent nightmares are associated with a blunted CAR. In the present pilot study we investigated the effect of acute nightmares on the CAR and the cortisol profile of the subsequent day using a within-subject ambulatory assessment study design. Thirty healthy volunteers who reported frequent nightmares enrolled in the study. Over a period of 14 days, salivary samples in addition to sleep-related and state variables were collected at home over the day. Salivary profiles of free cortisol and alpha amylase for up to two days following a nightmare were compared to those following a neutral dream. Overall, mood and health were decreased and the CAR was elevated following nightmares compared to neutral dreams. No differences were found for alpha amylase and for all variables over the remaining part of the day. Results suggest that sleep-related factors such as the occurrence of nightmares account for a certain amount of variance observed in the CAR. This has important methodological implications for CAR studies in general and might have even more relevance for studies in clinical populations suffering from chronic sleep disturbances.

Biomarking Trait Resilience With Salivary Cortisol in Chinese Undergraduates

This study aimed to examine the relationship between trait resilience and salivary cortisol in a group of Chinese undergraduates. The Chinese versions of the Brief Resilience Scale and a measure of optimism, the revised Life Orientation Test were administered to 49 Chinese undergraduates who provided self-collected saliva samples six times per day (immediately after waking; 0.5, 3, 6, and 12 h thereafter; and at bedtime) over 3 consecutive weekdays. The cortisol data were aggregated across the 3 days to examine the association between resilience and components of the diurnal rhythm of cortisol using multiple regression. The results showed that higher resilience was associated with a stronger cortisol response to awakening and a steeper diurnal decline in cortisol from waking to bedtime. Resilience was positively associated with cortisol output over the course of the day but this relationship was not significant (p = 0.065). This pattern of diurnal rhythm is consistent with that typically observed in better adjusted individuals. Generated by an intensive protocol with compliance objectively monitored, these findings clearly indicate the important role of the hypothalamic-pituitary-adrenocortical axis in health and adjustment and contribute to the growing literature on resilience and cortisol in humans.

Determinants of sleep quality in college students: A literature review

PURPOSE

To review the various determinants of sleep quality among college students.

METHODS

The PubMed, Web of Science and Cochrane Library databases were searched with the search string "sleep quality" AND "college students" for articles published between January 2007 and October 2017. Articles were excluded if they (1) examined sleep quality as a risk factor for other outcomes or (2) involved inpatients or participants under medical care.

RESULTS

The 112 identified studies were classified into categories according to the investigated determinants and their effect on sleep quality. Physical activity and healthy social relations improved sleep quality, while caffeine intake, stress and irregular sleep-wake patterns decreased sleep quality. Less consistent results were reported regarding eating habits and sleep knowledge, while proper napping during the day might improve overall sleep quality.

CONCLUSIONS

College students are vulnerable to different risk factors for sleep quality. When designing interventions to improve sleep quality among college students, the main determinants need to be taken into consideration.

Post-awakening Cortisol in Explosive Ordnance Disposal Technicians: A Replication Study in a Novel Population

INTRODUCTION

Amassing evidence suggests that post-awakening salivary cortisol rhythms (changes in cortisol throughout the day) may indicate health status. We previously established summary parameters for salivary cortisol in U.S. Navy Sea, Air, and Land and reported excellent parameter stability across 2 days of repeated sampling. To confirm the generalizability of our original findings to other military populations, we replicated the procedures of our prior report in another specialized military group. The purpose of this study was to (1) establish summary parameters of daily salivary cortisol rhythms, (2) evaluate summary parameter stability, and (3) assess the impact of sampling compliance in U.S. Navy Explosive Ordnance Disposal (EOD) technicians.

MATERIALS AND METHODS

Seventy active duty, male Explosive Ordnance Disposal technicians (mean ± SD age; 34.9 ± 6.5 years) self-collected saliva samples in a nondeployed setting on two consecutive weekdays at WAKE, WAKE + 30 min, WAKE + 60 min, 4 p.m., and 9 p.m. For salivary cortisol, we computed summary parameters, i.e., measures of magnitude and measures of pattern, and then evaluated their stabilities via correlational analyses and Cronbach's alpha (α). Compliance was objectively and subjectively evaluated using actigraphy and self-reported data, respectively. This research was conducted under a Naval Health Research Center Institutional Review Board approved study (NHRC.2015.0013).

RESULTS

Average salivary cortisol concentrations increased at WAKE + 30 (mean ± SE reactivity; 48.9 + 6.8%) from WAKE, followed by a swift recovery at WAKE + 60. Approximately 10.9% of the group were classified as negative-responders (i.e., < 0% change from WAKE to WAKE + 30). The measures of magnitude demonstrated fair stability across two days (r value range: 0.37-0.45, ps < 0.01; α range: 0.54-0.62). Fifty-five percent of the sample was classified as compliant (defined as <15 min deviation from target sampling times) across both days. Compliance decreased to 31% when compliance criteria were refined to <5 min deviation; however, controlling for compliance did not overwhelmingly influence the more stable summary parameters of magnitude.

CONCLUSIONS

These findings demonstrate a thorough replication, with some additional refinement, of our prior study, implying generalizability across diverse military populations. Study limitations include unsupervised saliva collection in a free-living setting, which is counterbalanced by ecological validity. The noninvasive salivary sampling protocol used in this study yields stable estimations of daily cortisol rhythms in specialized military men and is recommended as an operational health surveillance tool by which to monitor chronically stressed military members.

Daily rumination about stress, sleep, and diurnal cortisol activity

Rumination is an involuntary cognitive process theorized to prolong arousal and inhibit proper emotion regulation. Most available research has examined individual differences in cognitive dispositions to ruminate about stress as a risk marker for psychopathology and other health problems. This intensive longitudinal study extended previous research by examining day-to-day associations of rumination about stress with objectively-measured actigraph-based sleep and diurnal salivary cortisol activity. Sixty-one healthy participants (Mage = 20.91) completed up to five ecological momentary assessments (EMA) each day and wore actigraph wristwatches for eight days (N = 488). On three of these days, participants provided five saliva samples assayed for cortisol (N = 910). On average, greater daily stress levels were associated with shorter sleep duration and higher waking cortisol levels. In day-to-day analyses, greater daily stress levels, when combined with ruminating about daily stress more than usual, was associated with higher waking cortisol levels the following morning. Ruminating more than usual about daily stress, in the context of low-stress days, was also associated with flatter diurnal cortisol slopes the next day. These findings highlight the potential influences of daily stress, and rumination about stress, on sleep and diurnal cortisol activity - two important markers of health and well-being.

Challenges to Identity Integration Indirectly Link Experiences of Heterosexist and Racist Discrimination to Lower Waking Salivary Cortisol in Sexually Diverse Latinx Emerging Adults

Heterosexist and racist discrimination may adversely impact neurobiological processes implicated in the physical and psychosocial well-being of sexually diverse Latinx people. Yet, little is known about how experiences of both heterosexist and racist discrimination are associated with adrenocortical and psychological functioning in groups of people with multiply marginalized social group identities. Through the application of the intersectionality, minority stress, and allostatic load frameworks, it was hypothesized that experiences of heterosexist and racist discrimination would be associated with disruptions to diurnal salivary cortisol patterns and challenges to identity integration. A group of sexually diverse (self-identified lesbian, gay, bisexual, and queer) Latinx emerging adults (N = 51; ages 18-29, M = 24.06 years; SD = 2.73) provided saliva samples and completed a series of questionnaires during a four-day testing protocol. Heterosexist and racist discrimination were both positively associated with challenges to identity integration. Challenges to identity integration, in turn, were associated with lower intercepts of diurnal cortisol slopes, and heterosexist and racist discrimination were indirectly associated with lower cortisol intercepts via challenges to identity integration. These findings suggest that experiences of heterosexist and racist discrimination may interconnect by challenging sexual and ethnic/racial identity integration and disrupting adaptive adrenocortical regulation among sexually diverse Latinx emerging adults.

Waking Up on the Wrong Side of the Bed: The Effects of Stress Anticipation on Working Memory in Daily Life

Objectives

The aim of this study was to examine the association between stress anticipated for the upcoming day and cognitive function later on that day, and how this relationship differed across age.

Method

A diverse adult community sample (N = 240, age 25-65 years) completed ecological momentary assessment (EMA) reports for 2 weeks on a smartphone; each day they completed a morning survey upon waking, beeped surveys at five times during a day, and an end-of-day survey. Morning and end-of-day surveys included questions to measure stress anticipation, and each beeped survey included measures of stressful events, followed by a spatial working memory (WM) task.

Results

Results from multilevel models indicated that stress anticipation reported upon waking, but not on the previous night, was associated with deficit in WM performance later that day; importantly, this effect was over and above the effect of EMA-reported stress. The detrimental effect of stress anticipation upon waking was invariant across age.

Discussion

These findings suggest that anticipatory processes can produce harmful effects on cognitive functioning that are independent of everyday stress experiences. This may identify an important avenue to mitigate everyday cognitive lapses among older adults.

Tomorrow's gonna suck: Today's stress anticipation predicts tomorrow's post-awakening cortisol increase

The cortisol awakening response (a rapid rise in cortisol concentration shortly after awakening) is hypothesized to prepare the organism to cope with upcoming demands, suggesting a key role for anticipatory stress in its regulation. Yet, no thorough test of this hypothesis incorporating temporal dynamics of the underlying processes has been conducted so far. To address this gap in the literature, the present study investigated the effects of anticipated stress for the next day (assessed in the evening) on an estimate of the cortisol awakening response (assessed in the following morning). In an ambulatory assessment paradigm, 42 participants (69% female; mean age = 22.8, range = 18-30 years) completed 5 consecutive days of assessments in their daily lives, collecting saliva samples at awakening and 30 min later. Using hierarchical linear modeling, associations with anticipatory stress were examined separately on the within- and between-person level. In line with our expectations, anticipatory stress predicted the post-awakening cortisol increase on the within-person level, implying an elevated cortisol rise on days for which more stress than usual had been anticipated. In contrast, on the between-person level higher average anticipatory stress did not predict an increased cortisol rise. Taken together, the findings confirm a key role of anticipatory stress in the regulation of the cortisol awakening response on the within-person level.

Associations between cortisol awakening response and resting electroencephalograph asymmetry

The cortisol awakening response (CAR), a rapid cortisol rise in the morning after awakening, has been proposed to provide energy to cope with daily demands and suggested to be associated with brain functions. Electroencephalogram (EEG) asymmetry studies have implicated asymmetric cortical activation, especially in frontal cortex, in approach-withdrawal motivation. In this study, we examined the relationship between the CAR and lateralized cortical activity under rest in 55 university male students. Saliva samples were collected at 0, 15, 30 and 60 min after awakening on the two consecutive workdays. The lateralized cortical activity at frontocentral sites was examined by alpha asymmetry score. The results showed that a higher CAR was positively associated with alpha asymmetry score, which indicated that the higher CAR is linked with more left-sided cortical activity at frontocentral sites under resting state. This association still existed even after controlling psychological and sleep quality variables. These results suggested that appropriately mobilizing energy resource storage after awakening revealed as CAR might be associated with goal-directed approach tendencies before any eventual stressful situation, characteristic of more left than right resting-state frontocentral cortical activity.

Salivary Cortisol Profile Under Different Stressful Situations in Female College Students: Moderating Role of Anxiety and Sleep

Supplemental digital content is available in the text.

Objectives: This study investigated the level of cortisol under different stressful situations and its relationship with sleep and anxiety in female college students. Methods: Salivary cortisol was measured 6 times a day during a routine period free of examination stress and a stressful period. Area under the curve (AUC) was calculated for cortisol level for awakening response (AUC_AG) and during the day (AUC_TG). Sleep characteristics and anxiety were measured using an actigraph and the Spielberger State-Trait Anxiety Inventory, respectively, during the different periods. Results: Thirty-six people participated in the study. During the stressful period, anxiety had a positive correlation with sleep efficiency (P = .020), wake after sleep onset (P = .023), and mean wake episodes during sleep (P = .048). Poorer sleep efficiency (P = .014), greater wake after sleep onset (P = .008), and mean wake episodes during sleep (P = .044) were significantly associated with less AUC_AG. Trait anxiety was significantly higher in participants with greater AUC_TG (P = .008). Conclusions: Female college students with increased anxiety under the stressful situation slept better. Those with poor sleep showed attenuated morning cortisol secretion. Those with higher trait anxiety had greater cortisol during the day.

Sleep Architecture and Hypothalamic-Pituitary-Adrenal Activity in Paradoxical and Psychophysiological Insomnia

Introduction:

There are controversial reports about association between sleep and Hypothalamic-Pituitary-Adrenal (HPA) activity. Studies have reported the influence of insomnia on HPA hormones. However, they usually ignored the heterogeneity of insomnia symptoms, so subtypes of the disorder have not been considered in the reports. The present study aimed to investigate the final and intermediate products of HPA system among a group of psychophysiological and paradoxical insomniac patients in comparison to a group of normal sleepers.

Methods:

We investigated the awakening serum level of Adrenocorticotropic Hormone (ACTH) and cortisol after one night Polysomnography (PSG) in 17 subjects with psychophysiological insomnia, 19 subjects with paradoxical insomnia and 17 subjects with normal sleep profile. Groups were matched for age and Body Mass Index (BMI). Serum levels of ACTH and cortisol were measured by Enzyme-Linked Immunosorbent Assay (ELISA) method.

Results:

Although, a tendency toward elevation of both ACTH and cortisol was observed among patients with paradoxical insomnia compared to both control and psychophysiological insomnia, the differences were not significant comparing three groups. According to regression analysis, higher Non-Rapid Eye Movement sleep (NREM) arousal and Pulse Transit Time (PTT) significantly predicted higher level of ACTH.

Conclusion:

These findings could suggest the personality traits hypothesis for paradoxical insomnia. Both cortical and subcortical arousal could lead to more HPA activity and higher ACTH level. Further studies are recommended to confirm the hypothesis.

Variability of the cortisol awakening response and morning salivary oxytocin in late adolescence

Exogenously administered oxytocin interacts with the hypothalamic-pituitary-adrenal (HPA) axis to modulate endogenous cortisol levels, suggesting a synergistic role for these two hormones in the response to stress, cognitive performance and the development of psycho-behavioural disorders. The cortisol awakening response (CAR) is considered a reliable measure of HPA axis function in humans. However, the CAR appears to vary considerably from day to day and may be strongly influenced by the anticipated demands of the day ahead. The level of variation intrinsic to the CAR is unclear because few studies have examined the CAR in the absence of daily environmental variation. It is not known whether oxytocin has a similar or complementary awakening response. Therefore, over three consecutive days, we examined 12 adolescents (aged 15-17 years) in a highly-controlled sleep laboratory. Saliva was collected on days 4-6 of a 9-day laboratory visit. Cortisol and oxytocin levels were determined by an enzyme-linked immunosorbent assay from saliva sampled at 0, 15, 30 and 45 minutes, and 8 and 12 hours post-awakening. CAR magnitude varied between days and was associated with sleep duration and pre-awakening sleep stage. Conversely, oxytocin levels dropped dramatically in the first 15 minutes post-awakening and were highly consistent across participants and days. Older participants had higher awakening oxytocin concentrations. Although cortisol increases and oxytocin rapidly declines upon awakening, their diurnal variation does not appear to be related at basal, peripheral levels, consistent with a previous finding that exogenously administered oxytocin only modulates cortisol under conditions of stress.

Altered ultradian cortisol rhythmicity as a potential neurobiologic substrate for chronic insomnia

Chronic insomnia is highly prevalent and associated with significant morbidity (i.e., confers risk for multiple psychiatric and medical disorders, such as depression and hypertension). Therefore, it is essential to identify factors that perpetuate this disorder. One candidate factor in the neurobiology of chronic insomnia is hypothalamic-pituitary-adrenal-axis dysregulation, and in particular, alterations in circadian cortisol rhythmicity. Cortisol secretory patterns, however, fluctuate with both a circadian and an ultradian rhythm (i.e., pulses every 60-120 min). Ultradian cortisol pulses are thought to be involved in the maintenance of wakefulness during the day and their relative absence at night may allow for the consolidation of sleep and/or shorter nocturnal awakenings. It is possible that the wakefulness that occurs in chronic insomnia may be associated with the aberrant occurrence of cortisol pulses at night. While cortisol pulses naturally occur with transient awakenings, it may also be the case that cortisol pulsatility becomes a conditioned phenomenon that predisposes one to awaken and/or experience prolonged nocturnal awakenings. The current review summarizes the literature on cortisol rhythmicity in subjects with chronic insomnia, and proffers the suggestion that it may be abnormalities in the ultradian rather than circadian cortisol that is associated with the pathophysiology of insomnia.

Psychosocial functioning and the cortisol awakening response: Meta-analysis, P-curve analysis, and evaluation of the evidential value in existing studies

Cortisol levels rise immediately after awakening and peak approximately 30-45min thereafter. Psychosocial functioning influences this cortisol awakening response (CAR), but there is considerable heterogeneity in the literature. The current study used p-curve and meta-analysis on 709 findings from 212 studies to test the evidential value and estimate effect sizes of four sets of findings: those associating worse psychosocial functioning with higher or lower cortisol increase relative to the waking period (CARi) and to the output of the waking period (AUCw). All four sets of findings demonstrated evidential value. Psychosocial predictors explained 1%-3.6% of variance in CARi and AUCw responses. Based on these effect sizes, cross-sectional studies assessing CAR would need a minimum sample size of 617-783 to detect true effects with 80% power. Depression was linked to higher AUCw and posttraumatic stress to lower AUCw, whereas inconclusive results were obtained for predictor-specific effects on CARi. Suggestions for future CAR research are discussed.

Sleep and Physiological Dysregulation: A Closer Look at Sleep Intraindividual Variability

Study Objectives

Variable daily sleep (ie, higher intraindividual variability; IIV) is associated with negative health consequences, but potential physiological mechanisms are poorly understood. This study examined how the IIV of sleep timing, duration, and quality is associated with physiological dysregulation, with diurnal cortisol trajectories as a proximal outcome and allostatic load (AL) as a multisystem distal outcome.

Methods

Participants are 436 adults (Mage ± standard deviation = 54.1 ± 11.7, 60.3% women) from the Midlife in the United States study. Sleep was objectively assessed using 7-day actigraphy. Diurnal cortisol was measured via saliva samples (four/day for 4 consecutive days). AL was measured using 23 biomarkers from seven systems (inflammatory, hypothalamic-pituitary-adrenal axis, metabolic glucose and lipid, cardiovascular, parasympathetic, sympathetic) using a validated bifactor model. Linear and quadratic effects of sleep IIV were estimated using a validated Bayesian model.

Results

Controlling for covariates, more variable sleep timing (p = .04 for risetime, p = .097 for bedtime) and total sleep time (TST; p = .02), but not mean sleep variables, were associated with flatter cortisol diurnal slope. More variable sleep onset latency and wake after sleep onset, later average bedtime, and shorter TST were associated with higher AL adjusting for age and sex (p-values < .05); after controlling for all covariates, however, only later mean bedtime remained significantly associated with higher AL (p = .04).

Conclusions

In a community sample of adults, more variable sleep patterns were associated with blunted diurnal cortisol trajectories but not with higher multisystem physiological dysregulation. The associations between sleep IIV and overall health are likely complex, including multiple biopsychosocial determinants and require further investigation.

Cortisol Awakening Response as a Prospective Risk Factor for Depressive Symptoms in Women After Treatment for Breast Cancer

OBJECTIVE

The aim of the study was to investigate hypothalamic-pituitary-adrenal axis (HPA axis) functioning as a neurobiological risk factor for depressive symptoms in an ongoing longitudinal, observational study of women undergoing treatment and recovery from breast cancer. Many women with breast cancer experience depressive symptoms that interfere with their treatment, recovery, and quality of life. Psychosocial risk factors for depression among patients with cancer and survivors have been identified, yet neurobiological risk factors in this population remain largely unexamined.

METHODS

Women recently diagnosed with early-stage breast cancer (N = 135) were enrolled before starting neoadjuvant/adjuvant treatment (radiation, chemotherapy, endocrine therapy). At baseline, participants collected saliva samples to measure diurnal HPA axis functioning for 3 days: at waking, 30 minutes after waking, 8 hours after waking, and bedtime. Participants also completed a standardized measure of depressive symptoms (Center for Epidemiological Studies-Depression Scale) at baseline and 6 months after completion of primary treatment. Multivariate regression was used to predict continuous depressive symptoms at 6-month posttreatment from continuous depressive symptoms at baseline, cortisol awakening response (CAR), and other measures of diurnal HPA axis functioning.

RESULTS

The magnitude of CAR predicted changes in depressive symptoms over time, such that women with a higher CAR showed a greater increase from baseline to 6-month posttreatment (b = 5.67, p = .023). Diurnal slope and total cortisol output were not associated with concurrent depressive symptoms or their change over time.

CONCLUSIONS

Elevated CAR may be a neurobiological risk factor for increases in depressive symptoms in the months after breast cancer treatment and warrants further investigation.

Children's diurnal cortisol responses to negative events at school and home

This study examined the within-and between-person associations between daily negative events - peer problems, academic problems and interparental conflict - and diurnal cortisol in school-age children. Salivary cortisol levels were assessed four times per day (at wakeup, 30min later, just before dinner and at bedtime) on eight days in 47 youths ages 8-13 years old (60% female; M age=11.28, SD=1.50). The relative contributions of within- and between-person variances in each stressor were estimated in models predicting same-day diurnal cortisol slope, same-day bedtime cortisol, and next morning wakeup cortisol. Children who reported more peer problems on average showed flatter slopes of cortisol decline from wakeup to bedtime. However, children secreted more cortisol at wakeup following days when they had reported more peer or academic problems than usual. Interparental conflict was not significantly associated with diurnal cortisol. Findings from this study extend our understanding of short-term cortisol responses to naturally occurring problems in daily life, and help to differentiate these daily processes from the cumulative effects of chronic stress.

The Cortisol Awakening Response and Depressive Symptomatology: The Moderating Role of Sleep and Gender

The association between depression and the cortisol awakening response (CAR) has been widely examined, yet the results are mixed and factors responsible for such inconsistencies are poorly understood. The current study investigated whether the link between depressive symptomatology and CAR varied as a function of two such factors: sleep and gender. The sample included 58 young adults (30 females; M_age  = 18.7; SD_age  = 0.91). Participants completed the Beck Depression Inventory as well as the Consensus Sleep Diary to assess depressive symptomatology and daily sleep patterns, respectively. Participants also provided four salivary cortisol samples (0, 30, 45 and 60 min after awakening) during two consecutive weekdays. Results demonstrated that greater depressive symptoms were associated with a greater CAR but only when depressive symptoms were linked to a shorter sleep time. In addition, gender significantly moderated the association between depressive symptoms and CAR. While greater depressive symptoms were associated with an elevated CAR among females, they were associated with a blunted CAR among males. These findings provide some insight into potential mechanisms linking depressive symptomatology and CAR, and suggest that future studies examining CAR as a biomarker of depression should account for differences in sleep and gender. Copyright © 2016 John Wiley & Sons, Ltd.

Child anxiety symptoms related to longitudinal cortisol trajectories and acute stress responses: evidence of developmental stress sensitization

Cross-sectional research suggests that individuals at risk for internalizing disorders show differential activation levels and/or dynamics of stress-sensitive physiological systems, possibly reflecting a process of stress sensitization. However, there is little longitudinal research to clarify how the development of these systems over time relates to activation during acute stress, and how aspects of such activation map onto internalizing symptoms. We investigated children's (n = 107) diurnal hypothalamic-pituitary-adrenal activity via salivary cortisol (morning and evening levels) across 29 assessments spanning 6+ years, and related longitudinal patterns to acute stress responses at the end of this period (age 9-10). Associations with child psychiatric symptoms at age 10 were also examined to determine internalizing risk profiles. Increasing morning cortisol levels across assessments predicted less of a cortisol decline following interpersonal stress at age 9, and higher cortisol levels during performance stress at age 10. These same profiles of high and/or sustained cortisol elevation during psychosocial stress were associated with child anxiety symptoms. Results suggest developmental sensitization to stress-reflected in rising morning cortisol and eventual hyperactivation during acute stress exposure-may distinguish children at risk for internalizing disorders.

Sleep quality and health service utilization in Chinese general population: a cross-sectional study in Dongguan, China

OBJECTIVES

The aims of this study were to explore the Pittsburgh Sleep Quality Index (PSQI) and health service utilization in Chinese general population, to investigate the association between PSQI and health service utilization and to identify the independent contributions of social demographic variables, health related factors and PSQI to health service utilization.

METHODS

In a cross-sectional community-based health survey using a multi-instrument questionnaire, 4067 subjects (≥15 years old) were studied. The Chinese version of the PSQI was used to assess sleep quality. Health service utilization was measured by recent two-week physician visit and annual hospitalization rates.

RESULTS

Higher PSQI scores were associated with more frequent health service utilization. Higher scores in subjective sleep quality were associated with higher rate of recent two-week physician visit (adjusted OR = 1.24 per SD increase, P = 0.015). Higher scores in habitual sleep efficiency (adjusted OR = 1.24 per SD increase, P = 0.038) and sleep disturbances (adjusted OR = 2.09 per SD increase, P < 0.001) were associated with more frequent annual hospitalization. The independent influence of PSQI on the risk of recent two-week physician visit was 0.7%, and that of annual hospitalization 31.4%.

CONCLUSIONS

Poorer sleep quality predicted more frequent health service utilization. The independent contribution of PSQI on health service utilization was smaller than social demographic variables.

Daily family stress and HPA axis functioning during adolescence: The moderating role of sleep

The present study examined the moderating role of sleep in the association between family demands and conflict and hypothalamic-pituitary-adrenal (HPA) axis functioning in a sample of ethnically diverse adolescents (n=316). Adolescents completed daily diary reports of family demands and conflict for 15 days, and wore actigraph watches during the first 8 nights to assess sleep. Participants also provided five saliva samples for 3 consecutive days to assess diurnal cortisol rhythms. Regression analyses indicated that sleep latency and efficiency moderated the link between family demands and the cortisol awakening response. Specifically, family demands were related to a smaller cortisol awakening response only among adolescents with longer sleep latency and lower sleep efficiency. These results suggest that certain aspects of HPA axis functioning may be sensitive to family demands primarily in the context of longer sleep latency and lower sleep efficiency.

Change in parent-child conflict and the HPA-axis: Where should we be looking and for how long?

OBJECTIVE

Salivary cortisol is increasingly used as a longitudinal indicator of change in neuroendocrine regulation and as a predictor of health outcomes in youth. The purpose of this study was to describe which indices of HPA-axis functioning are sensitive to changes in parent-child conflict over a three week period and to explore the time course under which these changes can be measured.

METHODS

Youth (n=47; ages 8-13) completed daily diaries of their conflict with parents for 56 days. On days 17-18 and 38-39, youth contributed saliva samples upon waking, 30-minutes post-waking, afternoon, and bedtime. We assessed change in average diurnal HPA-axis functioning between day 17-18 and day 38-39 as a function of the slopes of change in parent-child conflict over 3 weeks.

RESULTS

Increasing parent-child conflict was positively associated with concurrent increases in total cortisol output (AUCg), flattening of the diurnal slope, and increases in cortisol at bedtime, but not with change in the cortisol awakening response (CAR). Further, associations between parent-child conflict and both AUCg and bedtime cortisol were observed with at least 14 days of daily diary reporting, whereas any additional ratings of conflict beyond 3 days of daily diaries did not improve model fit for changes in diurnal slope.

CONCLUSIONS

This study demonstrates the within-subject up-regulation of the HPA-axis across three weeks in a healthy sample of youth exposed to natural increases in family conflict. In particular, cortisol at bedtime may be the HPA-axis index that is most sensitive to change over time in parent-child conflict, above and beyond conflict occurring that day. Further, when testing associations between family stressors and diurnal cortisol, the optimal schedule for assessing parent-child conflict varies for different indices of HPA-axis functioning.

Examining multiple sleep behaviors and diurnal salivary cortisol and alpha-amylase: Within- and between-person associations

Sleep has been linked to the daily patterns of stress-responsive physiological systems, specifically the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). However, extant research examining sleep and diurnal patterns of cortisol, the primary end product of the HPA axis, has primarily focused on sleep duration with limited attention on other facets of sleep. For example, it is not clear how specific aspects of sleep (e.g., sleep quality, sleep duration variability) are related to specific components of diurnal cortisol rhythms. Salivary alpha-amylase (sAA) has been recognized as a surrogate marker of ANS activity, but limited research has explored relations between sleep and sAA diurnal rhythms. The current study utilized an ecological momentary assessment protocol to examine within- and between-person relations between several facets of sleep behavior using multiple methods (e.g., subjective report, actigraphy) and salivary cortisol and sAA. Older adolescents (N=76) provided saliva samples and diary entries five times per day over the course of three days. Sleep was assessed via questionnaire, through daily diaries, and monitored objectively using actigraphy over a four day period. Between-person results revealed that shorter average objective sleep duration and greater sleep duration variability were related to lower levels of waking cortisol and flatter diurnal slopes across the day. Within-person results revealed that on nights when individuals slept for shorter durations than usual they also had lower levels of waking cortisol the next day. Sleep was not related to the cortisol awakening response (CAR) or diurnal patterns of sAA, in either between-person or within-person analyses. However, typical sleep behaviors measured via questionnaire were related to waking levels of sAA. Overall, this study provides a greater understanding of how multiple components of sleep, measured in naturalistic environments, are related to cortisol and sAA diurnal rhythms, and how day-to-day, within-person changes in sleep duration contribute to daily variations in cortisol.

Sleep Moderates and Mediates the Relationship Between Acculturation and Depressive Symptoms in Pregnant Mexican-American Women

OBJECTIVE

Greater acculturation is associated with adverse perinatal outcomes in Mexican-American women, but the mechanisms by which acculturation influences perinatal outcomes are unclear. Pregnant acculturated Mexican-American women are more likely to engage in unhealthy prenatal behaviors relative to those less acculturated, including poor sleep. As sleep disruptions are associated with acculturation and negative perinatal outcomes, particularly maternal depression, alterations in sleep may adversely affect pregnant Mexican-American women.

METHODS

Sixty pregnant women of Mexican descent completed surveys about sleep, acculturation, depressive symptoms and potential protective factor of social support.

RESULTS

Acculturation, but not social support, significantly predicted increased sleep disruptions as well as overall feeling less refreshed upon waking across pregnancy. Moderation analysis indicated that more acculturated women who took longer to fall asleep reported increased depressive symptoms. Feeling refreshed upon waking also mediated the relationship between increased acculturation and elevated maternal depressive symptoms.

CONCLUSIONS

Acculturation and altered sleep contribute to greater risk in Mexican-American women for maternal depressive symptoms in the perinatal period. These findings have implications for prevention and treatment of maternal mental health disorders, which may adversely affect perinatal outcomes in the vulnerable Mexican-American population.

Sleep Quality Among Psychiatry Residents

OBJECTIVE

Medical residency programs are traditionally known for long working hours, which can be associated with a poor quality of sleep and daytime sleepiness. However, few studies have focused on this theme. Our objective was to investigate sleep quality, daytime sleepiness, and their relation with anxiety, social phobia, and depressive symptoms.

METHODS

This cross-sectional observational study involved 59 psychiatry residents. The Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS) were used to measure the quality of sleep and excessive daytime sleepiness ([EDS] and ESS > 10), respectively.

RESULTS

Among the 59 psychiatry residents, 59.3% had poor sleep quality (PSQI > 5) and 28.8% had EDS. Poor sleep quality was associated with higher EDS (P = 0.03) and the year of residency program (P = 0.03). Only 20% of residents with poor sleep had consulted at least once for sleep problems; 54.2% had used medications for sleep; and 16.9% were using medications at the time of interview. Only 30% obtained medication during medical consultations. Poor sleep was associated with irregular sleep hours (P = 0.001) and long periods lying down without sleep (P = 0.03). Poor sleep quality was also associated with high scores of anxiety symptoms (P < 0.001) and social phobia symptoms (P = 0.02).

CONCLUSION

Psychiatry residents frequently have poor sleep quality and EDS. Considering that sleep disorders can affect quality of life, predispose to metabolic syndrome, and be associated with worse performance at work, attention to this clinical problem is needed.

Age of Trauma Onset and HPA Axis Dysregulation Among Trauma-Exposed Youth

The hypothalamic-pituitary-adrenal axis (HPA axis) is a pathway through which childhood trauma may increase risk for negative health outcomes. The HPA axis is sensitive to stress throughout development; however, few studies have examined whether timing of exposure to childhood trauma is related to differences in later HPA axis functioning. Therefore, we examined the association between age of first trauma and HPA axis functioning among adolescents, and whether these associations varied by sex. Parents of 97 youth (aged 9-16 years) completed the Early Trauma Inventory (ETI), and youth completed the Socially-Evaluated Cold-Pressor Task (SECPT). We measured salivary cortisol response to the SECPT, the cortisol awakening response, and diurnal regulation at home across 2 consecutive weekdays. Exposure to trauma during infancy related to delayed cortisol recovery from peak responses to acute stress, d = 0.23 to 0.42. Timing of trauma exposure related to diverging patterns of diurnal cortisol regulation for males, d = 0.55, and females, d = 0.57. Therefore, the HPA axis may be susceptible to developing acute stress dysregulation when exposed to trauma during infancy, whereas the consequences within circadian cortisol regulation may occur in the context of later trauma exposure and vary by sex. Further investigations are warranted to characterize HPA axis sensitivity to exposure to childhood trauma across child development.

Poor sleep as a pathophysiological pathway underlying the association between stressful experiences and the diurnal cortisol profile among children and adolescents

Recent evidence suggests that poor sleep is a potential pathway underlying the association between stressful experiences and the diurnal cortisol profile. However, existing findings are largely limited to adults. The present study examines whether poor sleep (duration, quality) mediates the relation between stressful experiences and the diurnal cortisol profile in children and adolescents. Children and adolescents (N = 220, M(age) = 12.62) provided six saliva samples over two days to derive cortisol indices (bedtime, AUCAG, AUCTG, slope(MAX)). Perceived stress, stressful life events, self-reported sleep duration, and sleep quality were measured. Using bootstrapping analyses, sleep quality mediated the relation between perceived stress and AUCTG (R(2) = 0.10, F(7, 212) = 3.55, p = .001; 95% BCI[0.09, 1.15]), as well as the relation between stressful life events and AUCTG (R(2) = 0.11, F(7, 212) = 3.69, p = .001; 95% BCI[0.40, 3.82]). These mediation models remained significant after adjusting for sleep duration, suggesting that poor sleep quality underlies the association between stressful experiences and the diurnal cortisol profile in children and adolescents. Longitudinal data combined with objectively-measured sleep is essential to further disentangle the complex association between sleep and stress.

Vulnerability to Stress-Related Sleep Disturbance and Insomnia: Investigating the Link with Comorbid Depressive Symptoms

Greater sleep difficulty following a challenging event, or a vulnerability to stress-related sleep disturbance (i.e., sleep reactivity), is characteristic of insomnia. However, insomnia is rarely observed in isolation; rather it is frequently seen in combination with other problems, such as depression. Despite the link between depression and increased sensitivity to stress, relatively little is known about the role sleep reactivity has in explaining variability in depressive symptoms. Therefore, the current study examined whether sleep reactivity was associated with depressive symptoms, and whether this relationship was mediated by insomnia. We assessed sleep reactivity, insomnia, and depressive symptoms among 2250 young adults (1244 female; M_age = 23.1, SD_age = 2.97) from the Colorado Longitudinal Twin Study and Community Twin Study. Results indicated that greater sleep reactivity was significantly associated with elevated depressive symptoms, and that this link was partially mediated by insomnia. This is one of the first studies to demonstrate an independent association between sleep reactivity and depressive symptomatology. These findings suggest that a greater sensitivity to stress-related sleep disturbance may also be a predisposing factor to depression, and highlight the need for a better understanding of sleep reactivity, as it may represent a more global vulnerability construct.