Sleepless Longing: Bidirectional Associations Between Sleep Quality and Prolonged Grief in Daily Life After Traumatic...

Sleep disturbances are common in bereavement, especially among those with prolonged grief disorder (PGD). While cross-sectional and longitudinal studies have linked PGD with poor sleep, the directionality and timing of these effects remain unclear. In the present study, we employed a 14-day ecological momentary assessment (EMA) protocol to examine the day-to-day associations between sleep and grief in a sample of 46 traumatically bereaved adults (M_age = 56.0, 78% female, Med_{time since loss} = 3.8 years). PG symptoms were assessed 5×/day and sleep quality each morning via a smartphone app. Linear mixed models were used to examine within-person, lagged effects of sleep quality on PG levels and vice versa. Results indicated that PG symptoms did not predict sleep quality the following night. However, lower sleep quality was associated with increased PG severity during the day (controlling for previous-day PG levels), although this effect was no longer significant in sensitivity analyses restricted to participants with more complete sleep data (≥ 50%). Exploratory post hoc analyses indicated that sleep quality was most strongly associated with PG levels in the morning, with the effect being attenuated later in the day. Altogether, these findings provide tentative support for a night-to-day, sleep-to-grief pathway, although both small effect sizes and variability in results underscore the need for replication in larger samples. While preliminary, these findings suggest that poor sleep may contribute to the exacerbation of PG symptoms in the short term, highlighting the need for further research into the temporal dynamics and potential causal mechanisms linking sleep and grief.