Coincident alcohol dependence and depression increases risk of suicidal ideation among Army National Guard soldiers

Abstract

Purpose Suicide rates among military service members have risen dramatically, while drivers remain poorly understood. We examined the relationship between coincident alcohol dependence and depression in shaping risk of suicidal ideation among National Guard forces. Methods We performed a longitudinal analysis using a randomly selected, population-based sample of Ohio Army National Guard soldiers. Telephone-based surveys of 1582 soldiers who participated in both wave 1 (2008–2009) and wave 2 (2009–2010) were analyzed. Results Odds ratios (ORs) for suicidal ideation among those with versus without alcohol dependence were similar among nondepressed (OR = 3.85 [95% confidence intervals (CIs) = 1.18–12.52]) and depressed individuals (OR = 3.13 [95% CI = 0.88–11.14]); multiplicative interaction was not observed. In contrast, the risk differences (RDs) among those with versus without alcohol dependence diverged for those without depression (RD = 0.04 [95% CI = 0.02–0.07]) compared with those with depression (RD = 0.11 [95% CI = 0.06–0.18]); strong evidence of additive interaction was observed. Conclusions We found that alcohol dependence and depression interact statistically in shaping risk for incident suicidal ideation among Army National Guard service members. A high-risk prevention approach including population-based screening for suicidality among patients with alcohol dependence, depression, and particularly those with both conditions is warranted in military populations.