774 Insomnia precedes suicidal ideation in a national longitudinal study of sleep continuity (NITES)

Abstract

Abstract Introduction Suicide is the 10th leading cause of death among US adults, and disrupted sleep significantly increases suicide risk. It is unclear, however, how quickly changes in sleep can affect suicidal thoughts and behaviors. Therefore, the present study explored whether insomnia, sleep continuity, and nightmares predicted subsequent suicidal thinking. Methods Data were drawn from N=1,248 individuals 35 years and older who were part of a 1-year prospective study of the natural history of insomnia. Suicidal ideation was measured biweekly from the Patient Health Questionnaire – 9 and dichotomized (Score = 0, No; Score > 0, Yes). The primary predictors were Insomnia Severity Index (ISI) score and total wake time, total sleep time, difficulty initiating/maintaining sleep, and nightmares (from daily sleep diaries). Predictors were averaged over the previous 2 weeks and measured 2 nights prior to measuring suicidal ideation. Data were modeled using generalized estimating equations to account for within-subject correlations and adjusted for age, sex, and race/ethnicity. Results A total of N=124 individuals (65% female) reported suicidal ideation during the study. In unadjusted models, no sleep variable was associated with subsequent suicidal ideation. However, after adjusting for age, sex, and race/ethnicity, insomnia severity was associated with subsequent suicidal ideation when averaged over the preceding 2 weeks (OR 1.09 per point on the ISI, 95% CI [1.03–1.16]) and measured 2 days prior (OR 1.11 per point on the ISI, 95% CI [1.01–1.22]). Stratified analyses showed that this effect was driven by age, with insomnia predicting suicidal ideation in individuals 55–64 and 65 and older. Conclusion Insomnia is a significant, proximal risk factor for suicidal ideation, particularly in older adults. Consequently, treatment of insomnia may represent an effective suicide risk reduction strategy. Support (if any) K24AG055602 R01AG041783