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Abstract Introduction Prior research has established that sleep disturbances and depression are associated. However, notable limitations exist across past studies, including the heavy use of between-person analyses that are often based on single time point measures, use of general “sleep disturbance” over well-defined facets of sleep, overreliance on self-reported sleep, and lack of attention to within-person effects and their interactions with group-level characteristics (e.g., shiftwork). To address these limitations, the current study examined relationships between daily sleep facets and depression in nurses across measurements (self-report, actigraphy) and moderators (shiftwork, intraindividual variability of sleep midpoint). Methods Participants were 349 nurses (90.83% female; 76.50% White; 89.20% non-Latinx; Mage = 39.13 years) who wore an Actiwatch and completed the Consensus Sleep Diary and Patient Health Questionnaire-2 for 14 days. Multilevel models examined the bidirectional associations between daily depression and sleep (i.e., sleep efficiency SE, quality SQ, duration, midpoint) across self-report and actigraphy measures. Shiftwork (day vs. night shift worker) and intraindividual standard deviation (iSD) of sleep midpoint were included as moderators in models. Results Daily depression and subjective SQ and SE were bidirectionally associated after covarying for gender, age, race, and ethnicity. On days when nurses experienced higher depression than their average, they experienced worse subjective SQ (b = -0.10, SE = 0.02, p .001) and SE (b = -0.47, SE = 0.18, p = .008) on the same day. In turn, when nurses experienced worse subjective SQ (b = -0.07, SE = 0.02, p .001) and SE (b = -0.01, SE = 0.00, p = .012) than their average, they experienced higher depression on the next day. Daily actigraphy-based sleep facets were not significantly associated with depression. Neither shiftwork nor iSD of sleep midpoint were significant moderators. Conclusion Results reveal bidirectional, daily associations between subjective, but not actigraphy-based, sleep and depression. This suggests one's perception of sleep may be more influential on and impacted by depression than how one more objectively slept. Intensive longitudinal approaches to understanding sleep and depression should continue to be utilized to allow for the establishment of temporal precedence and bidirectionality across granular time scales. Support (if any) NIAID R01AI128359-01 (PIs: Taylor & Kelly)
Kim et al. (Sat,) studied this question.