Alcohol use disorder as a moderator of the relationship between posttraumatic stress disorder and suicidality among military personnel.

BACKGROUND:Alcohol use disorder (AUD), posttraumatic stress disorder (PTSD), and suicide are substantial public health concerns among military service members, yet the nature of their relationships is not well understood. Here, we tested the hypothesis that AUD moderates the relationship between PTSD symptom severity and suicidal ideation. METHODS:This secondary analysis uses data collected at baseline for a randomized clinical trial. The sample consists of 160 active-duty service members from three service branches (Army, Air Force, and Navy). All participants met diagnostic criteria for PTSD and were not engaged in evidence-based PTSD treatment at the time of enrollment. Zero-inflated Poisson generalized linear regression models were used to test the associations of PTSD and AUD symptom severity with the presence and severity of suicidal ideation. RESULTS:Findings suggest that AUD symptom severity moderates (i.e., amplifies) the relationship between PTSD symptoms and severity of suicidal ideation among military personnel with untreated PTSD. Among service members with mild or absent AUD, we found no significant association between PTSD symptoms and the severity of suicidal ideation. However, when AUD severity was average (i.e., sample mean) or high (mean + 1SD), PTSD symptoms were significantly positively associated with the severity of suicidal ideation. CONCLUSIONS:This study highlights the importance of assessing AUD and PTSD as a part of suicide risk evaluations of veterans. The results also provide strong support for the maintenance and further development in the military health system of treatment programs that simultaneously address AUD and PTSD comorbidity.