Alexandra D. Ehrhardt

The study examined whether change in childhood interparental conflict (IPC) moderated links between change in adolescent IPC and sleep from adolescence to emerging adulthood. Participants (N = 351, 52% female, 67% European American, 32% African American, 1% biracial) from diverse socioeconomic backgrounds in the Southeastern United States completed five waves of data collection (Mages = 8, 10, 15, 17, 22) between 2005 and 2022. Actigraphs measured sleep duration and quality. Participants reported on parents’ IPC. Latent change score models examined change-on-change in IPC and sleep. Among those with histories of increasing childhood IPC, increases in adolescent IPC predicted increases in sleep activity (β = .24) and long-wake episodes (β = .22) and decreases in sleep efficiency (β = −.20) from adolescence to emerging adulthood. Findings are consistent with stress sensitization.

Sleep is a fundamental domain of development and has important implications for other key aspects of adaptation. Little is known about normative changes in sleep across adolescence and emerging adulthood and whether the change is linear or nonlinear. We examined growth trajectories of sleep across 9 years of development and individual differences in trajectories according to participants' race/ethnicity and sex assigned at birth. During each wave, we measured four key actigraphy-derived sleep parameters over 1 week, including duration (number of minutes spent asleep), efficiency (percentage of time scored as sleep), midpoint (preferences for morningness-eveningness), and consistency/variability in duration (night-to-night fluctuations in duration over 1 week). Participants (N = 295, 53% female, 69% European American/White, 30% African American/Black, and 1% biracial) from diverse socioeconomic backgrounds completed five waves of data (M_ages at each wave: 15, 16, 17, 22, and 24). We observed a cubic trajectory for sleep duration whereby sleep duration declined across adolescence, increased into emerging adulthood, and declined again from 22 to 24. Consistency/variability in sleep duration also exhibited a cubic trajectory. Nightly fluctuations in sleep duration decreased from 15 to 16, increased from 16 to 22, and decreased again from 22 to 24. We found a quadratic trajectory for sleep midpoint, indicating a progressively greater preference for eveningness. Sleep efficiency exhibited linear growth and improved over time. Differences in trajectories for sleep duration and sleep efficiency emerged based on participants' race and sex. Findings indicated significant changes in the developmental trajectories of four sleep parameters across adolescence and emerging adulthood and underscore the importance of nonlinear assessments. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Although maintaining stable friendships is an important developmental task for adolescents, there is limited understanding of whether adolescents' friendships vary from day to day and predict changes in emotional well-being. Therefore, the current daily diary study aimed to characterize the day-to-day consistency of adolescents' close friendships and investigate whether feeling close to the same friends from 1 day to the next (daily friend continuity) predicted daily mood. Fourteen consecutive days of friendship nominations and mood assessments were collected from 195 11^th-grade students (M_age = 16.48; SD_age = 0.53; 66% female). Variability statistics (intraclass correlations, root mean square of successive differences) indicated considerable fluctuations in the consistency of friendship closeness as perceived by adolescents across 2 weeks. Results from multilevel models demonstrated that greater friend continuity was associated with greater positive mood, but not negative mood, at both the within- and between-person level. The findings reveal inconsistency in whom adolescents feel closest over 2 weeks and suggest that maintaining closeness with the same friends from 1 day to the next bolsters adolescents' short-term emotional well-being. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Study Objectives: Youth from socioeconomically disadvantaged backgrounds and minoritized racial/ethnic groups face a greater risk for sleep disparities and poor cognitive/academic outcomes compared to their peers from higher socioeconomic status (SES) and majority racial/ethnic groups. This meta-analysis has two main objectives. First, it examined SES and racial/ethnic variables as moderators of the association between individual sleep parameters (i.e. objective duration, objective quality, subjective duration, subjective quality, schedule/chronobiology, and variability/consistency) and overall (i.e. combined assessment) cognitive/academic outcomes (e.g. memory, GPA). Second, it assessed sleep parameters and outcome domains as moderators of the association between sleep broadly (i.e. no distinction between various sleep parameters) and overall cognitive/academic outcomes to test whether the magnitude of the association varied across specific sleep parameters and outcome domains. Methods: Thirty-three studies comprising 410 effect sizes and 52 854 participants were included. The meta-analysis was conducted per best practices. Results: For sleep and cognitive functioning, the overall weighted effect was r = 0.11, 95% CI [0.08, 0.14], p < .001. Several significant differential associations between various sleep parameters and cognitive functioning emerged, showing that some parameters were stronger predictors. Academic performance yielded similar results, with an overall weighted effect size of r = 0.14, 95% CI [0.10, 0.17], p < .001. SES and race/ethnicity also modified relations between certain sleep parameters and cognitive/academic functioning. Conclusions: The findings provide evidence for SES and race/ethnicity-related disparities, highlighting areas requiring further investigation. The discussion addresses methodological limitations in studying SES and race/ethnicity in relation to sleep and offers future research directions.

Emerging evidence suggests that whereas occupying high peer status promotes adolescents’ well-being, feeling dominated by friends confers psychological costs. However, little is known about day-to-day power dynamics of adolescents’ friendships or their acute affective consequences. This 14-day intensive longitudinal study introduced novel daily assessments of friend dominance and friendship clout, examined their associations with mood, and tested anxiety as a moderator. Participants were 195 11^th-graders (M_age = 16.48, SD_age = 0.35; 66% female). Multilevel models revealed that adolescents experienced worse mood on days they felt dominated by friends and better mood on days they felt powerful and influential among friends. Associations with negative mood were strongest for adolescents higher in anxiety. The findings underscore the dynamic nature of power in adolescents’ friendships.

Friendships are developmentally significant peer relationships that meaningfully contribute to adolescent adjustment. Despite extensive evidence that friendships contribute to adolescents’ psychological well‐being and mental health, less is known about the connections between adolescents’ friendships and physical health outcomes. Therefore, the current review synthesizes a growing body of research examining associations between adolescent friendships and physical health. The findings reviewed provide evidence for links between the quantity, quality, and stability of adolescents’ friendships and their corresponding subjective and physiological health. Consistency of findings varied as a function of friendship dimensions and health outcomes studied. In turn, we end the review with a discussion of conceptual and methodological consistencies and inconsistencies across the studies reviewed, a proposed agenda for future research, and a presentation of a novel process‐oriented model explaining how friendships may contribute to adolescent physical health.

Although peer relationships become increasingly important across adolescence and early adulthood, research examining links between peer relationships and the health outcomes of young people with as...

Introduction: Although prior research has considered how friendship quality or quantity influence peer victimization risk and vice versa, considerably less is known about how friendship instability (i.e., high levels of friend turnover) and peer victimization may be related to each other across time.Methods: Survey data were collected from 9th grade students (N = 388; M_age = 14.05; 60.60% female; 35.8% male; 1.8% non‐binary; 1.9% trans/unsure/something else) across 3‐month intervals spanning one school year. Using cross‐lagged panel modeling, this study investigated cross‐lagged longitudinal associations between friendship instability and peer victimization utilizing three waves of data collected across one academic year.Results: Adolescents experiencing greater peer victimization at the beginning of the school year were more likely to experience friendship instability by the end of the school year. However, friendship instability at the beginning of the school year was unrelated to subsequent peer victimization.Conclusion: Peer victimized adolescents are less likely than their nonvictimized peers to maintain stable friendships over time. Findings suggest that adolescents who are victimized by peers after transitioning to high school may have difficulty maintaining friendships.

The current longitudinal study examined how between-person (BP) differences and within-person (WP) fluctuations in adolescents’ peer victimization and schooling format across ninth grade related to changes in their internalizing symptoms during the COVID-19 pandemic. Participants were 388 adolescents (61% female;M_age= 14.02) who completed three online surveys, administered 3 months apart, from November 2020 to May 2021. Multilevel modeling revealed BP (time-invariant) and WP (time-varying) effects of peer victimization and school instructional format (i.e., in-person; hybrid; online) on internalizing symptoms while accounting for potentially confounding demographic (e.g., gender) and contextual (e.g., COVID-19 positivity rates) factors. Results indicated that adolescents who experienced higher overall levels of peer victimization across the school year, compared to those who experienced lower victimization, reported more severe internalizing symptoms. Whereas relative WP increases in peer victimization predicted corresponding increases in adolescents’ depressive and somatic symptoms regardless of schooling format, WP increases in peer victimization only predicted elevated anxiety during months when students attended fully in-person, but not online, school. Adolescents who spent a greater proportion of their school year attending online school also reported less peer victimization across the year. Findings highlight WP fluctuations in the effects of peer victimization on internalizing and contextual variations depending on schooling format.