Abstract
INTRODUCTION: Sleep disorder symptoms are associated with suicidal ideation, and wakefulness in the middle of the night is associated with an increased risk for suicide, potentially due to deficits in cognitive control. Little is known about daily-level associations among sleep and suicide or about the role of cognitive control in these associations. METHODS: Veterans (n = 32) with past-month suicidal ideation in a residential treatment unit were assessed for 28 days using the suicide visual analogue scale (S-VAS) to assess suicidal urges, a daily sleep diary, and self-reported cognitive control. RESULTS: Wakefulness in the middle of the night (1-4 a.m.) was associated with the most severe suicidal ideation. Nocturnal wakefulness and sleep quality were each associated with next-day suicidal ideation intensity. Self-reported cognitive control deficits were associated with more intense suicidal ideation. The association between nocturnal wakefulness and suicidal ideation was partially accounted for by self-reported impulsive behavior (7% of variance). CONCLUSIONS: Veterans reported the highest suicidal ideation in the middle of the night. These findings suggest the importance of assessing sleep, suicidal ideation, and cognitive control among veterans and the need to consider nocturnal wakefulness as an indicator of heightened risk for suicide among veterans.