Purpose-Suicide rates among military service members have risen dramatically, while drivers remain poorly understood. We aimed to examine the relationship between coincident alcohol dependence and depression in shaping subsequent risk of suicidal ideation among National Guard forces. Results-Incident suicidal ideation was present among 2.47% of soldiers at follow-up. Odds ratios (ORs) for suicidal ideation among those with vs. without alcohol dependence were similar among non-depressed [OR=3.85 (95% Confidence Intervals(CI) = 1.18-12.52)] and depressed individuals [OR = 3.13 (95% CI = 0.88-11.14)]; a logistic model cross-product term confirmed an absence of multiplicative interaction (beta coefficient=−0.21, p=0.82). In contrast, the risk differences (RD) for suicidal ideation among those with vs. without alcohol dependence diverged for those without depression [RD = 0.04 (95% CI = 0.02-0.07)] compared to those with depression [RD 0.11(95% CI=0.06-0.18)]; strong evidence of additive interaction was observed -[Relative Excess Risk of Interaction (RERI) = 5.978(95% CI=0.364-11.591)].
Methods-WeConclusions-We found that alcohol dependence and depression worked together to shape risk for incident suicidal ideation among Army National Guard service members. Because coincident alcohol dependence and depression is relatively rare, a high-risk prevention approach is