Some Combat Experiences May Increase Risk of Attempting Suicide among Service Members

BACKGROUND:
Suicide rates in the US military increased during the peak of the wars in Iraq and Afghanistan, prompting an examination of potential causes. Previous research among service members has identified many suicide risk factors that are comparable to the risks among civilians, including mental disorders, behavioral factors, and relationship problems, but uncertainty remains about the role that certain aspects of military deployments may play in suicide-related outcomes. This cohort study sought to determine the association of combat exposure with suicide attempts among active-duty US service members who were deployed in Iraq and Afghanistan. Using data from the Millennium Cohort Study (longitudinal study examining the long-term health effects of military service), investigators identified 57,841 active duty service members (76% male, 73% white) who were enrolled in that study between July 1, 2001, and April 4, 2013 and had completed a self-administered survey at enrollment and every 3-5 years thereafter. Suicide attempts among these service members were ascertained from military medical encounter data (using ICD-9 codes) between October 1, 2000 to September 30, 2015.

FINDINGS:

• When defined broadly, combat was not associated with suicide attempts after adjusting for demographic and military-specific factors.
• High combat severity was associated with an increased risk for suicide attempts, although this association was partly mediated by mental health disorders, specifically PTSD.
• Some individual combat experiences were associated with suicide attempts, but these associations were largely accounted for by mental disorders. Exceptions included being attacked or ambushed, seeing dead bodies or human remains, and being directly responsible for the death of a non-combatant, which showed significant associations with suicide attempts even after adjustment for mental disorders.

IMPLICATIONS:

• Results suggest that certain types of combat experiences may have different implications for service members compared to other combat experiences, increasing individuals’ risk of attempting suicide. Clinicians should be aware of the importance of inquiring about the nature of combat experiences, as well as continuing to identify and treat PTSD.

LIMITATIONS:

• The use of ICD-9 codes to identify suicide attempts may have underestimated the true number of attempts given that they may not have been associated with a healthcare visit or specific ICD-9 diagnostic code. Participants also may have sought care elsewhere.

AUTHOR/FUNDING INFORMATION:
This study was funded by the DoD and VA. Dr. Reger is Chief of Psychology Services at the VA Puget Sound Health Care System, and is part of HSR&D’s Center of Innovation for Veteran-Centered and Value Driven Care. Dr. Boyko is part of the Epidemiologic Research and Information Center (ERIC) and Chair of CSP #505: Millennium Cohort Study. Drs. Reger and Boyko are based in Seattle, WA.

LeardMann C, Matsuno R, Boyko E, Powell T, Reger M, and Hoge C. for the Millennium Cohort Study. Association of Combat Experiences with Suicide Attempts among Active-Duty US Service Members. JAMA Network Open. February 2, 2021;4(2); e2036065.