Mean Levels and Variability in Psychological Well-Being and Associations With Sleep in Midlife and Older Women.

BACKGROUND: Disturbed sleep is prevalent in older adulthood and particularly among women. Greater psychological well-being (PWB) is associated with better sleep, but intraindividual variability in PWB has not been examined. PURPOSE: The current study examined whether mean levels and variability in PWB were associated with sleep disturbances in midlife and older women. METHODS: Participants (N = 189) completed up to seven daily diaries and an end of the week assessment every 3 months for nine waves. Participants answered questions about their nightly sleep disturbances and reported their PWB using Ryff's six dimensions of PWB. RESULTS: Regression models indicated that greater variability in one aspect of PWB, positive relations with others, was related to greater sleep disturbance even after adjusting for mean levels of well-being. Greater variability in environmental mastery, purpose in life, and self-acceptance were also associated with sleep disturbance, but these associations were no longer significant after adjusting for mean levels of well-being. CONCLUSIONS: Results suggest that fluctuations in positive relations with others are related to sleep in adult women above and beyond mean levels of well-being. Results highlight the importance of considering variability in addition to mean levels of PWB.