Predictors of insomnia symptoms and nightmares among individuals with post-traumatic stress disorder: an ecological momentary assessment study.

Despite the high levels of comorbidity between post-traumatic stress disorder (PTSD) and sleep disturbance, little research has examined the predictors of insomnia and nightmares in this population. The current study tested both PTSD-specific (i.e. PTSD symptoms, comorbid anxiety and depression, nightmares and fear of sleep) and insomnia-specific (i.e. dysfunctional beliefs about sleep, insomnia-related safety behaviours and daily stressors) predictors of sleep quality, efficiency and nightmares in a sample of 30 individuals with PTSD. Participants participated in ecological momentary assessment to determine how daily changes in PTSD- and insomnia-related factors lead to changes in sleep. Multi-level modelling analyses indicated that, after accounting for baseline PTSD symptom severity, PTSD-specific factors were associated with insomnia symptoms, but insomnia-specific factors were not. Only daytime PTSD symptoms and fear of sleep predicted nightmares. Both sleep- and PTSD-related factors play a role in maintaining insomnia among those with PTSD, while nightmares seem to be linked more closely with only PTSD-related factors.