Levels of the stress-sensitive hormone cortisol increase dramatically in the first 30-40 minutes after waking, an effect known as the cortisol awakening response (CAR). There is considerable crosssectional evidence that psychosocial stress is associated with an increased CAR, and the CAR has been found to be altered in the presence of stress-related diseases, including Major Depressive Disorder (MDD). To date, no prospective longitudinal studies have examined whether individual differences in the CAR serve as a premorbid risk factor for MDD. In a sample of 230 late adolescents, clinical diagnoses of MDD were predicted from the CAR as well as other indicators of basal cortisol functioning gathered one year earlier, including: waking cortisol levels, bedtime cortisol levels, the size of the CAR, average cortisol, and the slope of the diurnal cortisol rhythm across the waking day. Age and gender, health and health behaviors, baseline neuroticism, exposure to stressful life events and past episodes of mood and anxiety disorders were included as covariates, to help ensure effects are attributable to the CAR rather than related variables. A higher baseline CAR was associated with a significantly increased risk of developing MDD by follow-up, even when excluding individuals with baseline MDD. No other baseline cortisol measures were significant prospective predictors of MDD. In summary, the CAR is a significant prospective risk factor for the development of MDD in young adults, providing some support for the possibility that a heightened CAR may play a role in the etiology of Major Depressive Disorder.

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Summary In attempts to understand the social determinants of health, strong associations have been found between measures of loneliness, physiological stress processes, and physical and mental health outcomes. Feelings of loneliness are hypothesized to have implications for physiological stress processes, including activity of the hypothalamic-pituitary-adrenal (HPA) axis. In a community sample of young adults, multilevel modeling was used to examine whether trait and state feelings of loneliness were related to changes in levels of the stress-sensitive hormone cortisol, and whether the associations between loneliness and cortisol were mediated or moderated by the presence of concurrent depression or high levels of chronic life stress. Results indicated that trait loneliness was associated with a flattening of the diurnal cortisol rhythm. In addition, both daily and momentary state variations in loneliness were related to cortisol. Prior-day feelings of loneliness were associated with an increased cortisol awakening response the next morning and momentary experiences of loneliness during the day were associated with momentary increases in cortisol among youth who also had high chronic interpersonal stress. Results were significant after covarying current depression, both chronic and momentary reports of stress, and medical and lifestyle covariates. This study expanded on prior work by investigating and revealing three different time-courses of association between loneliness and HPA axis activity in young adults: trait, daily and momentary.

Background The cortisol awakening response (CAR) has been shown to predict major depressive episodes (MDEs) over a 1-year period. It is unknown whether this effect: (a) is stable over longer periods of time; (b) is independent of prospective stressful life events; and (c) differentially predicts first onsets or recurrences of MDEs. Method A total of 270 older adolescents (mean age 17.06 years at cortisol measurement) from the larger prospective Northwestern-UCLA Youth Emotion Project completed baseline diagnostic and life stress interviews, questionnaires, and a 3-day cortisol sampling protocol measuring the CAR and diurnal rhythm, as well as up to four annual follow-up interviews of diagnoses and life stress. Results Non-proportional person-month survival analyses revealed that higher levels of the baseline CAR significantly predict MDEs for 2.5 years following cortisol measurement. However, the strength of prediction of depressive episodes significantly decays over time, with the CAR no longer significantly predicting MDEs after 2.5 years. Elevations in the CAR did not significantly increase vulnerability to prospective major stressful life events. They did, however, predict MDE recurrences more strongly than first onsets. Conclusions These results suggest that a high CAR represents a time-limited risk factor for onsets of MDEs, which increases risk for depression independently of future major stressful life events. Possible explanations for the stronger effect of the CAR for predicting MDE recurrences than first onsets are discussed.

Alterations in hypothalamic–pituitary–adrenal (HPA) axis functioning have been associated with major depression disorder (MDD) and some anxiety disorders. Few researchers have tested the possibility that high levels of recent life stress or elevations in negative emotion may partially account for the HPA axis alterations observed in these disorders. In a sample of 300 adolescents from the Youth Emotion Project, we examined associations between MDD and anxiety disorders, dimensional measures of internalizing symptomatology, life stress, mood on the days of cortisol testing, and HPA axis functioning. Adolescents with a past MDD episode and those with a recent MDD episode comorbid with an anxiety disorder had flatter diurnal cortisol slopes than adolescents without a history of internalizing disorders. Higher reports of general distress, a dimension of internalizing symptomatology, were also associated with flatter slopes. Negative emotion, specifically sadness and loneliness, was associated with flatter slopes and partially accounted for the associations between comorbid MDD and anxiety disorders and cortisol. The associations between past MDD and cortisol slopes were not accounted for by negative emotion, dimensional variation in internalizing symptomatology, or levels of life stress, indicating that flatter cortisol slopes may also be a “scar” marker of past experiences of MDD.

A growing body of research has demonstrated links between sleep problems and symptoms of depression and anxiety in community and clinical samples of adolescents and young adults. Scant longitudinal research, however, has examined reciprocal associations over socio-contextual shifts such as the transition to college. Using multiple methods of assessment (e.g., actigraphy, subjective report), the current study assessed whether sleep quantity, quality or variability changed over the transition to college and investigated the potential cross-lagged relationships between adolescents' sleep and symptoms of anxiety and depression. The participants (N = 82; 24% male) were studied at three time points over approximately 1 year: spring of their senior year of high school (T1), fall of their first year of college (T2), and spring of their first year of college (T3). Sleep minutes, sleep efficiency, wake time variability and anxiety increased over the transition to college. Subjective reports of sleep problems decreased. Cross-lagged panel models indicated significant relationships between subjective sleep quality and anxiety symptoms over time where subjective sleep problems at T1 were associated with anxiety at T2, and anxiety at T2 was associated with subjective sleep problems at T3. In contrast, greater depressive symptoms at T1 preceded increases in subjective sleep problems, sleep latency and sleep start time variability at T2. Importantly, there were concurrent associations between symptoms of anxiety or depression at T2 and sleep efficiency, sleep start time variability, and subjective sleep problems. These findings suggest that, overall, sleep quantity and quality improved over the transition to college, although the overall amounts of sleep were still below developmental recommendations. However, for some youth, the first semester of college may be a sensitive period for both sleep problems and symptoms of anxiety. In contrast, depressive symptoms were stable across time but were associated with worsening sleep problems in the first semester of college. Implications for future prevention and intervention programs should include strategies to help youth cope effectively with adjustment like increased sleep variability and symptoms of anxiety associated with the transition to college.

Health-related behaviors in adolescence establish trajectories of risk for obesity and chronic degenerative diseases, and they represent an important pathway through which socio-economic environments shape patterns of morbidity and mortality. Most behaviors that promote health involve making choices that may not pay off until the future, but the factors that predict an individual's investment in future health are not known. In this paper we consider whether expectations for the future in two domains relevant to adolescents in the U.S.—perceived chances of living to middle age and perceived chances of attending college—are associated with an individual's engagement in behaviors that protect health in the long run. We focus on adolescence as an important life stage during which habits formed may shape trajectories of disease risk later in life. We use data from a large, nationally representative sample of American youth (the US National Longitudinal Study of Adolescent Health) to predict levels of physical activity, fast food consumption, and cigarette smoking in young adulthood in relation to perceived life chances in adolescence, controlling for baseline health behaviors and a wide range of potentially confounding factors. We found that adolescents who rated their chances of attending college more highly exercised more frequently and smoked fewer cigarettes in young adulthood. Adolescents with higher expectations of living to age 35 smoked fewer cigarettes as young adults. Parental education was a significant predictor of perceived life chances, as well as health behaviors, but for each outcome the effects of perceived life chances were independent of, and often stronger than, parental education. Perceived life chances in adolescence may therefore play an important role in establishing individual trajectories of health, and in contributing to social gradients in population health.

Perceived discrimination remains a salient and significant environmental stressor for ethnic and racial minority youth. Although many studies have examined the impact of racial/ethnic discrimination on mental health symptomatology and physical health, little is known of the potential physiological processes underlying such experiences, especially during adolescence. In an attempt to understand how varying perceptions of discrimination relate to functioning of the hypothalamic-pituitary-adrenal axis (HPA axis), the current study examined the relation between Mexican American adolescents’ (N= 100, Mage = 15.3 years old) perceptions of discrimination and aspects of their diurnal cortisol profiles. Three salivary samples (wakeup, +30 waking, bedtime) were collected across three days (total of 9 samples). Utilizing multi-level modeling, results revealed that adolescents’ perceived discrimination related to greater overall cortisol output (area under the curve; AUC) after controlling for other life stressors, depressive symptoms, family income, acculturation level, daily stress levels and daily behaviors. Findings also revealed that perceived discrimination was marginally related to a steeper cortisol awakening response (CAR). Together, these findings suggest that perceived discrimination is a salient and impactful stressor for Mexican American adolescents. Understanding the physiological correlates of discrimination can provide insight into larger health disparities among ethnic and racial minority individuals.