Differentiating Single and Multiple Suicide Attempters: What Nightmares Can Tell Us That Other Predictors Cannot.

Study Objectives: Although nightmares have been associated with suicidal behavior beyond well-known risk factors, the association between nightmares and multiple suicide attempts remains largely unexplored. This study addressed this gap in the literature by examining whether nightmares differentiated between individuals who reported single versus multiple suicide attempts. The individual contributions of nightmare frequency, distress/severity, and chronicity were also investigated to determine which variable contributed the most variance. Methods: Participants (n = 225) were recruited as part of a larger data collection through Amazon Mechanical Turk, an online crowdsourcing venue. Participants reported attempting suicide once (n =107 individuals), multiple times (n = 118), or never (n = 791). Nightmare frequency, distress, and chronicity were assessed with the Disturbing Dreams and Nightmares Severity Index. Results: Nightmare frequency differentiated multiple from single suicide attempters, even after controlling for symptoms of depression, posttraumatic stress disorder, insomnia, nightmare severity/distress, nightmare chronicity, and age (P = .019). Comparison participants, those not reporting suicide attempts, reported a significantly lower level of nightmare frequency than those reporting single or multiple suicide attempts. Conclusions: Inconsistent with past research, this study showed that nightmare frequency, and not nightmare chronicity or severity/distress, differentiated between single and multiple suicide attempters. This outcome suggests that the number of nightmares experienced may be more pertinent in predicting repeat suicide attempts than their duration or perceived severity. Study limitations include a cross-sectional design, a convenience sampling approach, a lack of control for previous treatment or length of time since last attempt, and a retrospective nightmare measure.