This study examined youth stressor reactivity in the form of links between daily stressors and adolescents' negative affect, physical health symptoms, and cortisol patterns. We also tested whether youth gender and parental warmth moderated these linkages. Participants were the children of employees in the information technology division of a large company (N = 132, mean age = 13.39 years, 55% female). Youth completed daily diary telephone interviews on 8 consecutive evenings and provided saliva samples at 4 time points over 4 days to assess daily stressors and youth physiological and affective functioning. Parental warmth was assessed during in-home interviews. Multilevel modeling was used to account for interdependencies in the data. Youth who experienced more daily stressors, on average, reported more negative affect and physical health symptoms, on average. Furthermore, on days youth reported more stressors than usual (compared to their own across-day average), they also exhibited more physical health symptoms, reduced evening cortisol decline (e.g., flatter slopes), higher bedtime cortisol, and more negative affect. Girls had stronger within-person linkages between daily stressors and daily negative affect than boys. Parental warmth moderated these within-person linkages: Youth who experienced more parental warmth had lower negative affect and steeper cortisol decline than usual on less stressful days. However, youth who experienced less parental warmth had higher negative affect and their cortisol levels declined less, even on days with lower-than-usual stress. Daily stressors are associated with youth's affective and physiological functioning, but parental warmth can support youth's stress recovery. (PsycINFO Database Record

According to family systems and life course theories, periods of intense change, such as early adolescence, can disrupt stable family systems, leading to changes in family relationships. In this longitudinal study, we investigate 2 types of change in parental hostility and warmth toward their children during early adolescence (Grades 6 to 8)-developmental trends (linear declines) and lability (within-person fluctuations around developmental trends)-and their linkages to youth substance use and delinquency in Grade 9 (N = 618). We also test if the linkages between lability and youth risky behavior are moderated by youth gender. After controlling for between-person differences in level and developmental trends, we find greater lability (more fluctuations) in youth-reported parents' warmth and hostility are associated with greater youth delinquency, tobacco use, and polysubstance use initiation. The associations between youth-reported lability in mother and father hostility and polysubstance use demonstrated an inverted U shape pattern: Moderate levels of lability were associated with higher substance use but very low and high lability was associated with relatively lower rates of substance use. Many of the linkages between lability and youth delinquency were significant for girls but not boys. Fewer effects of lability on youth outcomes were found using parent reports. Developmental trends in parents' warmth and hostility were also associated with youth delinquency. Lability has unique implications for youth adjustment, yet appears to differ by youth outcome, gender, and reporter. The discussion focuses on mechanisms that might link changes in parent-youth warmth and hostility to youth risky behavior. (PsycINFO Database Record