Background
Suicidal behavior among U.S. Army soldiers increased substantially during the wars in Iraq and Afghanistan, [
1,
2] with the rates of suicide death more than doubling from 2001 (9/100,000) through 2009 (22/100,000) and surpassing the adjusted civilian rate in 2008 [
3]. Although the Army has implemented a variety of screening [
4‐
6] and prevention programs, [
7] identifying soldiers at risk of suicide remains a significant challenge. Research on military suicide has often emphasized the importance of deployment history, with mixed results [
1,
3,
8‐
11]. Deployment experiences vary substantially depending on a soldier’s military occupation. A meta-analysis found that suicidal outcomes were more strongly associated with particular combat experiences (e.g., killing, exposure to death) than with deployment in general, [
12] suggesting that occupations characterized by direct combat exposure may have a higher suicide risk than other occupations [
13,
14].
Soldiers with a combat arms (CA) occupation (e.g., infantry, airborne) have the highest likelihood of combat exposure, including frequent contact with enemy forces and increased risk of death and injury. CA soldiers tend to be at high risk for posttraumatic stress reactions, suicidality, and other mental health problems relative to other military occupations [
15‐
17]. Special forces (SF) are elite, highly trained soldiers who engage in frequent, often unconventional warfare operations. Although SF is a branch of CA, it warrants distinct consideration. Soldiers who successfully complete the rigorous selection process and training for SF may have unique characteristics [
18‐
20] that make them more resilient than other soldiers [
21]. Combat medics (CM) are also of particular interest, as they serve dual roles as both soldiers and healthcare providers [
22]. CM can experience direct combat exposure while embedded with infantry units [
23,
24] and are also directly exposed to the severe injury and death of soldiers they attempt to save.
The relevance of occupation extends well beyond exposure to combat-related stressors. The content, duration, and stressors associated with training vary considerably by occupation. The first year of service is largely a time of training and carries particularly high risk for suicide attempts [
25,
26]. CM have intense performance demands during this time, including 16 weeks of Advanced Individual Training in which they must achieve proficiency equal to or greater than an emergency medical technician. The training demands on CA soldiers, while also intense, are very different in nature.
We examine the association of occupation with suicide attempts among enlisted soldiers in U.S. Army. Enlisted soldiers accounted for nearly 99% of suicide attempts from 2004 through 2009 [
26]. Using administrative data from the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS), [
27] we focus on CA, SF, and CM, three occupations with high likelihood of direct combat exposure. CA soldiers are traditionally a population of intense focus in military mental health research, however, less is known about the health and functioning of SF and CM soldiers. We also examined whether the association of occupation with suicide attempt varied by deployment status and time in service [
28,
29].
Discussion
We found that soldiers with a combat occupation had higher risk of suicide attempt than other soldiers, with the exception of SF. CA soldiers accounted for 26.0% of all enlisted suicide attempters, with an overall standardized risk of 417/100,000 PY (compared to 357/100,000 PY for other occupations). CM soldiers, while accounting for only 7.1% of attempters, had the highest standardized risk (504/100,000 PY). They also were more likely to attempt suicide than CA, a finding that persisted in males. The significant but modestly elevated odds for CA and CM versus AO persisted even after adjusting for previous mental health diagnosis. The unique aspects of military service, particularly during wartime, make it difficult to draw direct comparisons with the literature on suicide risk among civilian occupations. CA and CM soldiers share some similarities with police officers and emergency medical technicians, respectfully, two civilian occupational groups for which there is some evidence of elevated suicide risk [
39].
Despite having an occupation that typically includes intense combat exposure over multiple deployments, SF accounted for only 16 suicide attempters from 2004 to 2009, with a standardized risk (102/100,000 PY) considerably lower than other occupations. The resilience of SF [
21] may result from rigorous selection, intense training, [
40] strong unit cohesion, [
41] or psychological and biological characteristics [
18‐
20]. Research on SF is lacking, and efforts to reduce suicide risk and mental healthcare stigma remain high priorities [
42,
43]. Future Army STARRS studies with administrative data beyond 2009 will allow further examination of SF.
The higher risk for CA and CM varied by deployment status and time in service. CA and CM had higher risk if never or previously deployed, but occupation was unrelated to suicide attempt among those currently deployed. While there was a substantial difference in standardized risk in never deployed CM (801/100,000 PY) and CA (601/100,000 PY), there was virtually no difference in previously deployed (352 and 358/100,000 PY, respectively) [
44].
The odds of suicide attempt were higher for CM than CA and AO during the first year of service. First-year CM had the highest standardized risk of all occupations across deployment status and time in service (1313/100,000 PY). Monthly hazard rates during the first year of service suggest that CA, CM, and AO have different patterns of risk during training. While all soldiers demonstrated rapidly increasing risk from the first to second month of service, the patterns deviated thereafter (approximately the end of basic training). First-year risk among CA was bimodal, whereas risk for CM remained elevated until the latter half of the first year. Training-related stressors may be particularly difficult to manage for those with pre-existing vulnerabilities, such as the considerable proportion of new soldiers who report a pre-enlistment history of suicidal behavior and mental disorders [
45,
46].
After basic training CM undergo advanced training with high performance demands. A previous study found that mental health symptoms, including suicide ideation, increased over the course of CM training, and were associated with female gender and lower education [
47] Although about 24% of CM in our sample were females and all CA soldiers were male, we found that the differential risk between first-year CM and CA persisted in males, suggesting that CM-CA differences are not due to gender composition. The proportion of soldiers with less than a high school education was substantially less for CM (9.8%) than CA (17.8%). Future research should examine the timing and relationships between lower education, poor training performance, and risk of suicide attempt among CM.
This study has five noteworthy limitations. First, the suicide attempt data are from administrative records. Although perhaps including the most serious cases, these records are subject to errors in clinician diagnosis or medical coding, and would not capture attempts that did not result in medical treatment. Second, our findings may not generalize to other periods of the Iraq and Afghanistan wars, or to other military conflicts. Third, we focused on a specific subset of occupations, but alternative categorizations are possible [
48,
49]. In particular, there are a large number of occupations that fall under CA but are not as directly engaged in combat as a primary job function, e.g., combat engineers, which have elevated suicide deaths relative to the entire Army [
13]. The organization of military occupations is not static, but changes over time based on the Army’s needs and strategic decisions [
35,
36]. Fourth, we were not able to determine the degree to which the experiences and day-to-day responsibilities of individual soldiers corresponded to their assigned occupational code. Most significantly, these administrative data did not allow assessment of combat exposure. While all occupations considered have a high likelihood of direct combat exposure, actual exposure will vary. Finally, differences across deployment status and time in service are not evidence of within-person changes in suicide attempt risk over time, as the composition of these groups is affected by the non-random nature of deployment and Army retention and attrition [
50].
Acknowledgments
The Army STARRS Team consists of Co-Principal Investigators: Robert J. Ursano, MD (Uniformed Services University of the Health Sciences) and Murray B. Stein, MD, MPH (University of California San Diego and VA San Diego Healthcare System).
Site Principal Investigators: Steven Heeringa, PhD (University of Michigan), James Wagner, PhD (University of Michigan) and Ronald C. Kessler, PhD (Harvard Medical School).
Army liaison/consultant: Kenneth Cox, MD, MPH (USAPHC (Provisional)).
Other team members: Pablo A. Aliaga, MS (Uniformed Services University of the Health Sciences); COL David M. Benedek, MD (Uniformed Services University of the Health Sciences); Laura Campbell-Sills, PhD (University of California San Diego); Carol S. Fullerton, PhD (Uniformed Services University of the Health Sciences); Nancy Gebler, MA (University of Michigan); Robert K. Gifford, PhD (Uniformed Services University of the Health Sciences); Paul E. Hurwitz, MPH (Uniformed Services University of the Health Sciences); Sonia Jain, PhD (University of California San Diego); Tzu-Cheg Kao, PhD (Uniformed Services University of the Health Sciences); Lisa Lewandowski-Romps, PhD (University of Michigan); Holly Herberman Mash, PhD (Uniformed Services University of the Health Sciences); James E. McCarroll, PhD, MPH (Uniformed Services University of the Health Sciences); James A. Naifeh, PhD (Uniformed Services University of the Health Sciences); Tsz Hin Hinz Ng, MPH (Uniformed Services University of the Health Sciences); Matthew K. Nock, PhD (Harvard University); Nancy A. Sampson, BA (Harvard Medical School); CDR Patcho Santiago, MD, MPH (Uniformed Services University of the Health Sciences); LTC Gary H. Wynn, MD (Uniformed Services University of the Health Sciences); and Alan M. Zaslavsky, PhD (Harvard Medical School).
Authors’ contributions
CSF, HHM, JAN, MBS, MS, RCK, RJU, and SGH contributed to the study concept and design. CSF, GHW, HHM, HMD, JAN, JEM, MBS, MS, NAS, PAA, SGH, RCK, RJU, THHN, and TK were responsible for the acquisition, analysis, or interpretation of the data. CSF, HHM, JAN, PAA, RCK, THHN, and RJU were involved in drafting the manuscript. CSF, GHW, HMD, HHM, JAN, JEM, MBS, MS, NAS, PAA, SGH, RCK, RJU, THHN, and TK contributed to critical revision of the manuscript for important intellectual content. CSF, GHW, HHM, HMD, JAN, JEM, MBS, MS, NAS, PAA, SGH, RCK, RJU, THHN, and TK provided administrative, technical, and material support. All authors read and approved the final manuscript.