(PS8-4) First responders with high sleep reactivity may be more vulnerable to fear of sleep after nightmares

Abstract Text:

Introduction: Trauma-related nightmares (TRNs) affect approximately one quarter of first responders and may engender a fear of sleep (FoS), which is associated with more severe sleep disturbance and psychopathology in this population, including alcohol abuse, anxiety, depression, and posttraumatic stress disorder (PTSD). Thus, there is a need to identify which first responders are most vulnerable to a FoS following TRNs to guide intervention efforts. Nightmares may be most disruptive to the sleep of first responders with high sleep reactivity – a trait vulnerability to sleep disturbance – leading to sleep disruptions characterized by fear and anxiety (e.g., avoiding sleep to avoid nightmares). We tested whether sleep reactivity strengthened the association between TRNs and FoS.

Methods: We recruited 242 first responders within the United States (59.2% male, 86.4% white, 56.2% law enforcement officers, 98.7% active duty, Myears of service = 17.0). Participants completed a cross-sectional survey on TRNs (PTSD Checklist for DSM-5, Item 2, “How much have you been bothered by repeated, disturbing dreams of the stressful experience in the past week?” 0 = not at all to 4 = extremely), FoS (Fear of Sleep Index – Short Form), and sleep reactivity (Ford Insomnia Response to Stress Test; FIRST). We tested sleep reactivity as a moderator of the association between TRNs and FoS (TRNs × FIRST).

Results: Based on a median split (FIRST score ≥ 19), 48.7% of participants were categorized as highly sleep reactive (MFIRST = 19.96 ± 5.79 SD). We found a significant interaction effect, such that the relationship between TRNs and FoS was strongest for first responders with high FIRST (TRNs × FIRST: β = 0.30, ± 0.68 SE, p = 0.006). This interaction effect was robust to years of service and insomnia status (Insomnia Severity Index score ≥ 15). The full model accounted for 34% of the variance in FoS (adjusted R2 = 0.34, p = 0.011).

Conclusion: First responders with high sleep reactivity may be at increased risk of FoS after TRNs, perhaps because nightmares exploit a highly sensitive sleep system that leads to a sleep-disrupting fear response at bedtime (“Being in the dark scared me”).