Examination of the indirect effects of combat exposure on suicidal behavior in veterans

Background: Researchers have theorized that increased rates of suicide in the military are associated with combat exposure; however, this hypothesis has received inconsistent support in the literature, potentially because combat exposure may be indirectly related to suicide risk through its influence on posttraumatic stress disorder (PTSD) and depressive symptoms. The current study tested the hypothesis that combat exposure has a significant indirect effect on suicidal behavior among Iraq/Afghanistan-era veterans through its effects on PTSD-depressive symptomatology.

Methods: Iraq/Afghanistan-era veterans (N = 3,238) participated in a cross-sectional, multi-site study of post-deployment mental health consisting of clinical interviews and self-report questionnaires. Structural equation modeling (SEM) was used to examine direct and indirect relationships between three latent variables: combat exposure, PTSD-depression, and suicidal behavior (past attempts and current ideation, intent, and preparation).

Results: A partial mediation model was the best-fitting model for the data. Combat exposure was significantly associated with PTSD-depression (β = 0.50, p < .001), which was in turn associated with suicidal behavior (β = 0.62, p < .001). As expected, the indirect effect between combat exposure and suicidal behavior was statistically significant, β = 0.31, p < .001.

Limitations: Data were cross-sectional, and suicidal behavior was measured via self-report.

Conclusions: Results indicated that combat exposure was indirectly related to suicidal behavior via PTSD-depressive symptomatology. Findings lend support for a higher-order combined PTSD-depression latent factor and suggest that Iraq/Afghanistan-era veterans with high levels of PTSD-depressive symptoms are at increased risk for suicidal behavior.