1090 Irritability as a Proximal Mechanism Linking Daily Sleep and Suicidal Thoughts: An Intensive Monitoring Study with Adolescents

Abstract Introduction Over 1 in 5 US high school students report seriously considering suicide in the past year alone, making it essential to identify who is acutely at risk and when youth are most at risk for thinking about suicide. Although insufficient sleep (poor sleep quality and short sleep duration) are well-documented risk factors for suicide, less research has focused on potential mechanisms linking sleep and suicidal thinking. Irritability, which is separately linked to both insufficient sleep and suicide, may be a potential mechanism. The current study leveraged an intensive, real-time monitoring design for two months to examine sleep (quality, duration) and irritability as modifiable risk factors for suicidal thoughts among adolescents. Methods A total of 128 adolescents (Mean Age =15.9 years; 60% girls; 45% White) completed two months of ecological momentary assessment (EMA), including morning sleep diaries, irritability (3x/day), and evening-reported suicidal ideation. A subset of adolescents (N=63) wore actiwatches to capture behavioral sleep metrics during the two-month period. Multilevel modeling was used to examine whether individual fluctuations in sleep (quality, duration) predicted next-day irritability and suicidal ideation. Results Findings indicate that youth who reported worse sleep quality (t=-6.19, p<.001) and actigraphic-derived shorter sleep duration than usual (B=-2.34, p=.02) experienced more next-day irritability. Heightened irritability was associated with a greater likelihood of suicidal ideation that day (B=.56, p <.001). There were no direct links between sleep quality or duration and next-day suicidal thinking. Conclusion Poorer- and shorter-than-usual sleep may heighten next-day irritability, which may subsequently affect suicidal thinking in youth. Irritability may be a potential mechanism linking sleep and suicidal thinking in adolescents. This study highlights the importance of evaluating modifiable risk factors, such as sleep, and identifying potential mechanisms using intensive monitoring designs to inform interventions and prevent adolescent suicide. Support (if any) K01MH121584