Posttrauma nightmares are recurring nightmares that begin after a traumatic experience and can occur as often as multiple times per week, often in a seemingly random pattern. Although these nightmares are prevalent in trauma survivors, little is known about the mechanisms underlying their sporadic occurrence. The present study aimed to investigate predictors of posttrauma nightmares. The sample included 146 observations nested within 27 female college students who reported frequent nightmares related to sexual trauma. Participants were recruited from an undergraduate student subject pool (n = 71) or were clinical referrals (n = 75). Participants completed an initial assessment battery and six consecutive days of pre- and postsleep diaries, which included measures of potential posttrauma nightmare triggers and measures intended to assess sleep quality and posttrauma nightmare occurrence. Descriptive statistics, mean comparisons, and multilevel modeling were used to examine the data. The results showed that both presleep cognitive arousal, γ10 SLij = 0.58, p = .006, z(1, N = 146) = -2.61; and sleep latency (SL), γ20 PCAij = 0.76, p < .001, z(1, N = 146) = -2.69, predicted posttrauma nightmare occurrence. Further investigation suggested that presleep cognitive arousal moderated the relation between SL and posttrauma nightmare occurrence, γ30 PCA x SLij = 0.67, p = .048 z(1, N = 146) = 1.98. The present results are the first to show that the co-occurrence of presleep arousal and delayed sleep onset latency may influence posttrauma nightmare occurrence, suggesting that the time immediately before sleep is crucial to the production of the posttrauma nightmares.
© 2020 International Society for Traumatic Stress Studies.