Abstract Introduction Worry-related sleep problems—difficulty falling or staying asleep due to intrusive thoughts—reflect heightened cognitive–emotional hyperarousal that impairs emotion regulation and fosters negative, self-focused thinking. Although sleep disturbances are consistently associated with higher negative affect, less is known about how worry-driven sleep problems relate to broader dimensions of psychological and social well-being, such as self-acceptance and positive relations with others. Prior studies have mainly emphasized between-person differences, leaving a critical gap in understanding how within-person fluctuations in worry-related sleep problems correspond to changes in well-being. The present study addresses this gap by examining 20-year trajectories of worry-related sleep problems and evaluating their distinct within- and between-person associations with negative affect, self-acceptance, and positive relations across adulthood. Methods This study utilized three waves of data from the Midlife in the United States Study (MIDUS; N = 1,605; ages 24–74 at baseline; 58.9% female). Two forms of worry-related sleep problems were assessed: difficulty falling asleep and difficulty staying asleep. Linear growth models estimated trajectories of worry-related sleep problems over 20 years, and two-level multilevel models evaluated within-person and between-person associations between worry-related sleep problems and negative affect, self-acceptance, and positive relations, controlling for baseline age, education, sex, race, and ethnicity. Results Worry-related sleep initiation (p = .002) and maintenance problems (p .001) increased as participants aged. Higher sleep initiation problems were associated with higher negative affect, lower self-acceptance, and lower positive relations at both within-person and between-person levels (all ps .001). Higher sleep maintenance problems were associated with higher negative affect at both levels (all ps .001) and with lower self-acceptance and lower positive relations at the between-person level (all ps .001). Conclusion Trajectories indicated that worry-related sleep problems worsen with age across adulthood. Between-person effects showed consistently poorer well-being among adults with chronically higher worry-driven sleep problems. Within-person fluctuations were associated with higher negative affect, lower self-acceptance, and lower positive relations with others, suggesting the importance of monitoring changes in these sleep problems. These findings suggest that interventions targeting worry, hyperarousal, and sleep-related behavioral patterns—such as cognitive behavioral therapy for insomnia (CBT-I)—may help support emotional, psychological, and interpersonal well-being across adulthood. Support (if any) N/A
Eunjin Tracy (2026) studied this question.