Studies of the association between traumatic brain injury (TBI) and suicide attempt have yielded conflicting results. Furthermore, no studies have examined the possible mediating role of common comorbid psychiatric conditions in this association. This study used Veterans Affairs registry data to evaluate the associations between deployment-related TBI, psychiatric diagnoses, and attempted suicide among 273,591 veterans deployed in support of Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn, and who received care from the Department of Veterans Affairs during 2007-2012. We performed Cox proportional hazards regression analyses, adjusting for demographic characteristics. Mediation analyses were conducted to quantify the impact of psychiatric conditions (posttraumatic stress disorder, depression, anxiety, and substance abuse) on this association. The sample was predominantly male (84%); mean age = 28.7 years. Veterans with TBI (16%) were more likely to attempt suicide than those without (0.54% vs. 0.14%): adjusted hazards ratio = 3.76, 95% confidence interval: 3.15, 4.49. This association was attenuated in mediation analyses (adjusted hazards ratio = 1.25, 95% confidence interval: 1.07, 1.46), with 83% of the association of TBI with attempted suicide mediated by co-occurring psychiatric conditions and with posttraumatic stress disorder having the largest impact. These results suggest that veterans with these conditions should be closely monitored for suicidal behavior.

Fonda JR, Fredman L, Brogly SB, McGlinchey RE, Milberg WP, Gradus JL. Traumatic Brain Injury and Attempted Suicide Among Veterans of the Wars in Iraq and Afghanistan. Am J Epidemiol. 2017 Jul 15;186(2):220-226. doi: 10.1093/aje/kwx044. PMID: 28472407.