1123 Daily Alcohol Use Moderates the Association Between Poor Sleep Quality and Suicidal Ideation Severity

Abstract Introduction Alcohol dependence is a known risk factor for suicidal ideation and is associated with reduced sleep quality. Poor sleep quality is also associated with suicidal ideation and related behaviors. Despite this, the relationship between alcohol use, sleep quality, and suicidality remains underexplored. To address this gap in the literature, we examined whether daily alcohol use moderates the relationship between poor sleep quality and suicidal ideation severity. Methods Participants (N = 971) from the National Sleep Research Resource’s Assessing Nocturnal Sleep/Wake Effects on Risk of Suicide (ANSWERS) dataset answered a battery of questionnaires, including the Columbia Suicide Severity Rating Scale (C-SSRS), Pittsburgh Sleep Quality Index (PSQI), and a substance use survey. Bayesian ordinal regression was conducted in R to estimate the association between poor sleep quality and suicidal ideation severity in the past three months while controlling for age. Daily alcohol use was included as an interaction term. Posterior distributions were summarized using median odds ratios and 95% credible intervals. Results Poorer sleep quality was associated with greater past-three-month suicidal ideation severity (OR = 1.18, 95% CI [1.13, 1.24], pd = 100%). Daily alcohol use moderated this association: for individuals who drank daily, the relationship between poor sleep and suicidal ideation severity was stronger (interaction OR = 1.51, 95% CI [1.14, 2.11], pd = 99.85%). The main effect of daily drinking alone was highly uncertain (OR = 1.15, 95% CI [0.17, 7.72]). Conclusion In this sample, individuals with poorer sleep quality exhibited higher suicidal ideation severity in the past three months, and this association was amplified among those who consumed alcohol daily. These findings highlight the potential exacerbating effect of alcohol use on suicidality for populations with sleep difficulties. Future research should examine the influence of additional factors, such as minority status, gender, and other substance use. This research suggests the importance of targeted interventions for individuals who struggle with both sleep problems and excessive alcohol consumption. Support (if any)