P021 Daily association between post-traumatic stress symptoms and sleep in trauma-exposed young adults

Sleep disruptions and post-traumatic stress disorder (PTSD) are bi-directionally linked and have been found to mutually reinforce each other on a daily basis. However, most of the previous research has focused on subjective sleep measures only. In this study, we investigated the temporal relationship between sleep and PTSD symptoms using both subjective (sleep diary) and objective sleep measures (actigraphy) in 41 non-treatment seeking, trauma-exposed young adults (age M=24.68, SD=8.15) with a range of PTSD symptom severities (PTSS, 0-53 on PCL-5). Participants reported daily PTSS and number of intrusions as well as nightly sleep, while wearing an actigraphy watch over four weeks. Linear mixed models showed that subjectively reported sleep disruptions were associated with elevated next-day PTSS and more intrusions both within and between participants. Similar effects were found for PTSD symptoms influencing subsequent subjective sleep. However, these associations were not found in the objective sleep data. Exploratory moderator analyses including sex (male vs. female) suggested sex-specificity in these associations. While subjective sleep results were in line with previous research, objective sleep results differed. Several factors may underly the divergent findings, such as the COVID-19 pandemic and/ or sleep-wake state discrepancy. Although further research is required, these data suggest the relationship between sleep and PTSD symptoms differs between objective and subjective sleep measures and depending on sex.