LAUSR

Observational research demonstrates a strong association between nightmares, insomnia, and sleep apnea in veterans with posttraumatic stress disorder (PTSD), supportive of the notion of a “complex sleep disturbance”. Relations between sleep disturbances and PTSD are often bi-directional and disturbed sleep affects non-sleep PTSD outcomes. We aimed to examine relationships between nightmares, respiratory events, CPAP use, and insomnia in trauma-exposed veterans with frequent nightmares. Three weeks of app-based daily sleep diaries and weekly insomnia severity index (ISI) reports were collected from 41 veterans with a history of trauma and frequent nightmares. Relationships between weekly nightmares (total number), CPAP use, sleep efficiency, and ISI scores were analyzed using linear regression with standard errors adjusted for clustering of weeks within participants. Of the 41 participants, a subset of 15 participants completed 6-9 nights of at-home objective sleep measurements (Sleep Profiler) to examine the relationship between apnea events and nightmare awakenings. Measurements involved EEG integrated with airflow, respiratory effort, oxygen saturation, and actigraphy with event marker for real-time reporting of nightmares preceding awakenings. 41 veterans (mean age 48 (SD=16), 30% female) participated. Higher prior week ISI score predicted reduced CPAP adherence (β=-.53, p=.005). In turn, increased frequency and duration of CPAP use was associated with a significant increase in sleep efficiency the same week (β=.53, p=.018 and β=.56, p=.026, respectively). Analysis of respiratory events indicates that 20 of the 64 nightmare awakenings (31%) were preceded (i.e., within seconds of awakening) by apnea or hypopnea events. Of these 20, 11 events were reported by participants with a diagnosis of OSA and a CPAP device. Amongst these 11 events, 7 (64%) occurred on nights during which the participant reported use of their CPAP. Analyses demonstrated statistically significant and clinically meaningful relationships among insomnia, nightmares, respiratory events and CPAP adherence in our sample, highlighting their interrelationships in trauma subjects. These data support the hypothesis that OSA contributes to nightmare experiences by demonstrating an immediate temporal relationship between apnea/hypopnea events and nightmare awakenings, and they underscore the importance of detecting and adequately treating sleep apnea for the treatment of nightmares in veterans.