P008 The relationship between REM Sleep prior to Analogue Trauma and Intrusive Memories

Intrusive memories are a core feature of posttraumatic stress disorder (PTSD). They both predict the onset of the disorder and drive broader PTSD symptomology. Outside PTSD, disruptions in REM sleep contribute to emotional dysregulation and an amplified reaction to negative emotional stimuli. The current study examined the association between REM sleep prior to analogue trauma and intrusive memories. To manipulate REM sleep, 22 healthy adults (MAge = 26.05, SD = 5.22) were randomised to either to a circadian misalignment (CM) condition or normal control (NC) condition for four nights. In CM, participants slept normally for two nights followed by a 4-hour phase advance on night three and an additional 4-hour phase advance on night four. In NC, participants slept 8 hours. On the day after night 4, participants watched a trauma film in a controlled laboratory setting. Participants kept an intrusive memory diary for three days following viewing of the film. Greater REM sleep percentage across 4 nights prior to analogue trauma was significantly associated with fewer intrusive memories independent of group in the 3 days after viewing of the film (p = .015). Findings suggest REM sleep may serve to protect individuals against experiencing intrusive memories. This is consistent with evidence suggesting REM sleep influences the encoding of emotional memory. Occupations (e.g., emergency service workers/military personnel) who experience circadian disruptions likely to decrease REM sleep (e.g., from shift work) may be at heightened risk of experiencing intrusive memories after trauma exposure, and thus at increased risk of developing PTSD.