0422 EVALUATING THE ASSOCIATION BETWEEN INSOMNIA SUBTYPES AND SUICIDAL IDEATION AMONG ARMY SERVICEMEMBERS

Abstract Introduction: Past studies support an association between insomnia and suicidal ideation. Few studies, however, have parsed insomnia into its respective subtypes (i.e., early, middle, and late insomnia), to assess if one of the subtypes confers more risk for suicidal ideation than the others. To assess this possibility, the present study assessed associations between suicidal ideation (globally construed) and early, middle, and late insomnia, as well as the phenomenon of frequent awakenings. Methods: The sample consisted of 2,617 servicemembers that participated in the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS), a large epidemiological study examining the risk factors for suicidality. Insomnia variables included measures of early, middle, and late insomnia and frequent nocturnal awakenings. Depression was determined by whether or not the participant met criteria for a depressive episode during the past 30 days. Suicidal ideation was determined by whether or not participants endorsed any form of suicidal ideation during the same time frame. To determine the independent effect of each insomnia variable on suicidal ideation, a stepwise logistic regression was conducted. Insomnia and depression variables were entered as independent variables in the model, and suicidal ideation was entered as the dependent variable. Results: When controlling for depression [OR = 7.05, p < .001], only early insomnia [OR = 1.13, p = .02] and frequent awakenings [OR = 1.23, p < .001] emerged as significant predictors of suicidal ideation. Conclusion: The present data provide some insight into the specific nature of the relationship between insomnia and suicidal ideation, in that early insomnia (i.e., difficulty initiating sleep) and frequent awakenings were distinctly associated with a global measure of suicidal ideation. If these results are found to be reliable (over subsequent studies with similar and/or different populations and/or using prospective measures) such data may serve to focus future investigations on how insomnia confers risk for suicidality. Support (If Any): Army STARRS was funded by the US Department of Health and Human Services, National Institutes of Health, National Institute of Mental Health (NIH/NIMH; U01MH087981).