Abstract Introduction Sleep disturbances are common in older adults and are risk factors for depression and anxiety. Sleep and mood dysfunction both represent common symptoms in Parkinson’s disease (PD), but the association between them is not well understood. Here, we investigated whether sleep disturbance contributes to mood symptoms among older adults with and without PD. Methods Data were collected from 55 participants aged ≥ 50 (33 clinically unimpaired CU and 22 with PD), as part of a broader study evaluating cognitive decline and parkinsonism. Participants completed the Beck’s Depression Inventory (BDI) and State-Trait Anxiety Inventory (STAI), and daily ecological momentary assessments of morning depressed mood. Sleep was subjectively assessed with the Pittsburgh Sleep Quality Index (PSQI). At-home objective sleep data were recorded with an Oura™ device worn over 7-14 days assessing total sleep time (TST), sleep efficiency (SE), and REM and deep sleep proportion. Group differences and night-by-night associations were examined using ANCOVAs and linear mixed effects models including age as a covariate. Results PD participants reported worse mood relative to CU, with higher BDI (p 0.0001) and STAI (STAI-S: p=0.0009; STAI-T: p=0.01) scores and worse morning mood (p=0.002). PD participants also had worse subjective sleep quality with higher global PSQI scores (p=0.0001). For device-estimated measures of sleep, participants with PD had lower mean SE (p=0.002), TST (p=0.03), and REM sleep proportion (p 0.0001) than CU, but did not differ from CU in deep sleep proportion. Deep sleep proportion decreased with older age (p=0.005) irrespective of group. Analyses of nightly sleep, predicting next-morning depressed mood, showed that lower SE (p=0.03) and older age (p=0.003) predicted worse mood in both groups. However, shorter TST predicted next-morning depressed mood specifically in PD (TST-by-group interaction p=0.006). Conclusion Parkinson's disease is associated with worse subjective and objective sleep quality, and elevated depressive and anxiety symptoms. Beyond group differences, day-to-day variations in sleep efficiency predicted worse next-day mood, suggesting that poor sleep meaningfully contributes to mood. Improving night-to-night sleep efficiency in older adults, plus nightly total sleep time in people living with Parkinson's disease, may improve mood symptoms. Support (if any) AG081144
Shariff et al. (2026) studied this question.