Naturalistic fluctuations in night-to-night sleep duration and quality and their associations with next-day perceived stress and affect

Sleep problems and perceived stress are linked to mental health outcomes. Epidemiological studies suggest that the effect of perceived stress on depressive symptoms is partially mediated by poor sleep quality. Naturalistic associations among perceived stress, affect, sleep quality, and depressive symptoms have not been thoroughly explored. We examine within-person associations among sleep, perceived stress, and affect in a naturalistic setting and the moderating effect of depression. Participants were 167 individuals (136 women, 29 men, 2 other gender) who completed a 21-day daily diary assessment. Multilevel models revealed that perceived stress (b = -0.01, p = 0.04) and negative affect (b = -0.05, p = 0.04) were lower than usual following nights of longer than usual sleep duration. In participants experiencing depression, increases in last night’s sleep quality were associated with decreases in next-day perceived stress (b = -0.02, p = 0.001) and negative affect (b = -0.01, p < 0.001). Within-person mediation analyses indicated that last night’s sleep impacts negative affect via changes in perceived stress. Participants with depression experienced lower negative affect following nights of higher than usual sleep quality. Controlling for between-person differences in sleep duration and quality, within-person fluctuations in sleep duration and quality impacted next-day perceived stress and affect across populations. The daily functioning of individuals experiencing depression was especially sensitive to naturalistic fluctuations in sleep occurring in daily life, suggesting sleep may be a sensitive target for interventions that aim to reduce daily stress and negative affect in depression.