Nightly sleep duration predicts grade point average in the first year of college.

Academic achievement in the first year of college is critical for setting students on a pathway toward long-term academic and life success, yet little is known about the factors that shape early college academic achievement. Given the important role sleep plays in learning and memory, here we extend this work to evaluate whether nightly sleep duration predicts change in end-of-semester grade point average (GPA). First-year college students from three independent universities provided sleep actigraphy for a month early in their winter/spring academic term across five studies. Findings showed that greater early-term total nightly sleep duration predicted higher end-of-term GPA, an effect that persisted even after controlling for previous-term GPA and daytime sleep. Specifically, every additional hour of average nightly sleep duration early in the semester was associated with an 0.07 increase in end-of-term GPA. Sensitivity analyses using sleep thresholds also indicated that sleeping less than 6 h each night was a period where sleep shifted from helpful to harmful for end-of-term GPA, relative to previous-term GPA. Notably, predictive relationships with GPA were specific to total nightly sleep duration, and not other markers of sleep, such as the midpoint of a student's nightly sleep window or bedtime timing variability. These findings across five studies establish nightly sleep duration as an important factor in academic success and highlight the potential value of testing early academic term total sleep time interventions during the formative first year of college.

Lack of Belonging Predicts Depressive Symptomatology in College Students.

Feeling a sense of belonging is a central human motivation that has consequences for mental health and well-being, yet surprisingly little research has examined how belonging shapes mental health among young adults. In three data sets from two universities (exploratory study: N = 157; Confirmatory Study 1: N = 121; Confirmatory Study 2: n = 188 in winter term, n = 172 in spring term), we found that lower levels of daily-assessed feelings of belonging early and across the academic term predicted higher depressive symptoms at the end of the term. Furthermore, these relationships held when models controlled for baseline depressive symptoms, sense of social fit, and other social factors (loneliness and frequency of social interactions). These results highlight the relationship between feelings of belonging and depressive symptoms over and above other social factors. This work underscores the importance of daily-assessed feelings of belonging in predicting subsequent depressive symptoms and has implications for early detection and mental health interventions among young adults.

How is Mindfulness Linked to Negative and Positive Affect? Rumination as an Explanatory Process in a Prospective Longitudinal Study of Adolescents.

Research shows greater mindfulness is associated with less negative affect and more positive affect. Fewer studies have examined the mediating psychological processes linking mindfulness to these outcomes in adolescents. This three-wave, prospective longitudinal study examines rumination-the tendency to engage in repetitive and negative self-focused thinking-as one potential explanatory process. High school students (N = 599, Mage = 16.3 years; 49% girls) completed a short-form version of the Five Facet Mindfulness Questionnaire, in addition to self-report measures of rumination and negative and positive affect three times over the course of a school year. Autoregressive, cross-lagged panel models tested reciprocal, prospective associations between mindfulness, rumination, and negative and positive affect, while accounting for prior levels of each construct, within-wave covariances, and gender and grade level. The results showed that the nonjudgment mindfulness facet (and the total mindfulness score) predicted cross-wave reductions in rumination, that in turn predicted cross-wave reductions in negative affect. No evidence for mediation was found for positive affect, or for any of the other mindfulness facets (describe, acting with awareness, and nonreactivity). This study provides suggestive evidence that individual differences in mindfulness, and in particular nonjudgmental acceptance, prospectively predict less negative affect through lower rumination.