Temporal associations between nightmares and PTSD symptoms in the acute post-sexual assault period: An ecological momentary assessment study.

Nightmares are common after sexual assault and may play an important role in the development of posttraumatic stress disorder (PTSD). However, little research has examined daily temporal associations between nightmares and PTSD symptoms in the acute aftermath of sexual assault. Ecological momentary assessment (EMA) was used to test within- and between-person associations between nightmares and PTSD symptoms during the six weeks following assault. Participants were 54 women sexual assault survivors presenting for emergency care (Mage=24.64, 51.9% White, 29.6% Hispanic/Latina), followed with daily EMA surveys. Dynamic structural equation modeling (DSEM) was used to estimate lagged bidirectional associations between nightmares and PTSD symptoms. Most participants had clinically significant PTSD symptoms according to traditional self-report (97.9% at week one; 85.4% at week seven) and frequent nightmares measured by EMA (42.8% of days). At the within-person level, nightmares significantly predicted next-survey PTSD symptoms (the full model accounted for 18.4% of the within-level variance in PTSD), and PTSD symptoms significantly predicted subsequent nightmares (the full model accounted for 11.7% of the within-level variance in nightmares). However, these effects were no longer significant after adjusting for autoregressive effects. At the between-person level, individuals with frequent nightmares had higher PTSD symptoms and vice versa, with models accounting for 43.2-43.9% of the between-level variance. While nightmares are common in early recovery, short-term fluctuations in nightmare symptoms may not meaningfully drive PTSD symptoms changes once stability is considered. Nightmares may function as an indicator of overall PTSD severity, underscoring their importance in identifying survivors at risk for more severe PTSD symptoms.