P010 Extinction recall in PTSD after selective REM or SWS deprivation.

Abstract Aim Rapid eye movement (REM) sleep plays a critical role in processing emotional experiences by consolidating memories while reducing their affective intensity. In post-traumatic stress disorder (PTSD), REM sleep is frequently disrupted and may interfere with mechanisms central to recovery (fear extinction learning). However, most evidence linking REM sleep to extinction recall comes from studies in healthy individuals. This study is the first to investigate the effect of REM deprivation on extinction recall in trauma-exposed individuals with varying PTSD severity. Method Fifty-five participants (mean age = 25.85, SD = 6.97), including 18 with likely PTSD (PCL-5 > 31), completed a two-day fear conditioning paradigm. Following extinction learning, participants were randomly assigned to sleep during the first half of the night (REM deprivation), sleep during the second half (non-REM deprivation), or normal sleep. Extinction recall was assessed using subjective threat expectancy ratings and objective skin conductance response (SCR). Result Mixed-model ANOVA on threat expectancy revealed significant effects of stimulus, trial, and a three-way interaction between sleep condition, stimulus, and trial (p’s < .001, ηp2 > 0.14). Post-hoc analyses indicated a trend toward heightened threat expectancy in the REM-deprived group during early extinction recall trials. No significant differences were observed in SCR. Conclusion Although the a priori sample size (n = 84) has not yet been reached, these initial findings highlight that REM sleep disruption may selectively impair subjective aspects of extinction memory in PTSD, without corresponding changes in physiological arousal. This suggests that improving REM sleep may reduce exaggerated threat beliefs and enhance the effectiveness of exposure-based therapies for PTSD.