Study Finds Links Between Higher Individual, Unit Rates

BETHESDA, MD—Are soldiers in specific Army units more likely to attempt suicide? A new study looks at that issue and explores what characteristics of the units might influence the decision to take one’s own life.

The study, published recently in JAMA Psychiatry, found that the risk of suicide attempts (SA) among Army personnel is affected by a history of suicide and attempts in soldiers’ units. The study group, led by Robert J. Ursano, M.D., of the Uniformed Services University of the Health Sciences, suggested that the higher rate of unit SAs is linked to greater individual suicide risk, especially in smaller units.1

“Attention to unit characteristics by leadership and service professionals may be a component in SA reduction efforts,” study authors wrote. “Early unit-based postvention consisting of coordinated efforts to provide behavioral, psychosocial, spiritual, and public health support after SAs may be an essential tool in promoting recovery and suicide prevention in servicemembers.”

Data from the Army Study to Assess Risk and Resilience in Servicemembers (STARRS) was used to establish that connection. Researchers identified records for all active-duty, regular U.S. Army, enlisted soldiers who attempted suicide from 2004 through 2009 and focused on a final sample of re 9,512 enlisted soldiers.

Results indicated that soldiers were more likely to attempt suicide if one or more suicide attempts had occurred in their unit during the past year, with the odds increasing as the number of suicide attempts in a unit increased. In fact, soldiers in a unit with five or more suicide attempts in the past year had more than twice the odds of suicide attempt compared to those in units with no previous SAs.

Standardized Risk Estimates (SREs) of Suicide Attempt by Number of Past-Year Unit Suicide Attempts and Unit SizeThe SREs (number of soldiers who attempted suicide per 100 000 person-years) were calculated assuming other predictors were at their sample-wide means. The SREs were calculated separately for each unit size based on logistic regression models that included basic sociodemographic and service-related variables (sex, age at entry into the army, current age, race/ethnicity, educational level, marital status, time in service, deployment status, military occupation, and number of past-year unit suicide attempts) and included a dummy predictor variable for calendar month and year to control for secular trends.

The longitudinal cohort study of administrative records determined that the higher risk was present whether the unit was engaged in combat or otherwise and for units of all sizes, although the effect appeared to be magnified in smaller units of one to 40 soldiers.

While researchers have long known that mental health of soldiers is adversely affected by the death and injury of other unit members, it had been unclear whether the risk of suicide attempt is influenced by previous suicide attempts in a soldier’s unit, the researchers note.

In the study, most of the soldiers attempting suicide were:

  • male, 86.4%;
  • 29 years old or younger, 68.4%;
  • younger than 21 years when entering the army, 62.2%;
  • white, 59.8%;
  • high school educated, 76.6%; and
  • currently married, 54.8%.

After adjustment, study authors concluded that soldiers were more likely to attempt suicide if one or more suicide attempts occurred in their unit during the past year, for an odds ratio [OR] of 1.4-2.3. They further determined that odds increased with the number of unit attempts increased, with the odds of suicide attempt among soldiers in a unit with 5 or more past-year attempts have an OR of 2.3 compared to that of soldiers in a unit with no previous attempts. Risk also was substantial in the smaller units, 2.1-5.9.

“The population-attributable risk proportion for 1 or more unit suicide attempts in the attempts would not occur,” the authors pointed out.

That association persisted when examining the number of past-year unit suicide attempters—as opposed to instead of attempts—as the predictor, even when excluding soldiers in their first six months of service, those in Warrior Transition Units, and when adjusting for the number of soldiers within a soldier’s unit with a past-year mental health diagnosis.

Background information in the article noted that the suicide attempt rate among Army servicemembers increased substantially during the Iraq and Afghanistan wars. It observed that medically documented SAs generally are more likely to occur among soldiers never or previously deployed, as well as those who are female, younger, non-Hispanic white, less-educated and in the early stages of Army service, especially in the first months of training.

Study authors also emphasized the importance of units as the foundational structure of the Army.

“Soldiers have a variety of shared unit experiences, including exposure to external group stressors (e.g., training, deployment, and combat) and internal group stressors (e.g., leadership changes, bullying by peers or leaders, and injury or death of unit members),” the researchers wrote. “External group stressors, particularly combat, adversely affect the mental health and suicide risk of soldiers within a unit. Internal unit characteristics, including leadership quality and group cohesion, can exacerbate or mitigate the influence of external group stressors on performance and health-related outcomes, including suicide ideation.”

The authors noted that injuries and deaths from combat and unintentional events undoubtedly have an adverse effect on the mental and physical health of unit members. They suggested, however, that not as much is known about the influence of suicidal behavior on other unit members.

“Personal accounts suggest that suicidal events can have profound negative effects within a unit,” they write. “Suicide contagion, in which exposure to suicide is proposed to increase suicidal behaviors in others, even if the person who died was not personally known, may result in clustering or multiple suicidal behaviors exhibited in a short period and/or specific geographic area or community. Multiple suicidal events may also reflect high unit stress attributable to factors such as poor leadership or low group cohesion.”

The study emphasized that previous research has primarily focused on soldiers’ responses to suicide death, with less attention to responses after unit suicide attempts. The authors included data that nearly half of veterans report knowing someone who died by suicide and 65% of those knowing more than one person who took their own life. Exposure to suicide death is a predictor of suicide ideation and attempts in veterans and civilians, the authors pointed out.

“Contrary to previous findings, which relate generally to knowing someone who had died by suicide, unit deaths of any type, including suicide, were not significantly associated with risk of SA in our study,” according to the researchers. “Unit deaths are a more specific and circumscribed group than knowing someone, and the causal mechanisms and responses (e.g., of peers and leaders) may differ for unit suicide deaths vs attempts in an active-duty army unit. In addition, there is a lower frequency of unit deaths relative to unit SAs, which may make it harder to detect the influence of deaths in our sample. Intervention efforts that track unit SAs regardless of whether unit members were acquainted with the attempter may help identify at-risk groups.”

The study underscored the importance of unit characteristics—leadership quality, extent of social support and cohesion, and presence of bullying—critically influence culture and the likelihood of and responses to unit SAs.

Unit cohesion has been associated with reduced distress, increased resilience, and positive states of mind, the report noted, but, “To the extent that SAs among fellow soldiers disrupt a soldier’s sense of unit cohesion, our findings suggest that the negative effects may be strongest in smaller units. Similarly, the potential for contagion, particularly within smaller units, is worthy of further study.”

Limitations of the study include the possibility of diagnostic or coding errors. Also, the data focus on the 2004 through 2009 period and the findings may not be generalizable to earlier and later periods of the Iraq and Afghanistan wars or to other U.S. military conflicts, the researchers said.

An accompanying editorial written by Charles W. Hoge, MD, of the Center for Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, and the Behavioral Health Division, Office of the Army Surgeon General, Falls Church, VA, and colleagues, talks about the unique challenges faced by the Army in combating suicide.

“Between 2005 and 2009, during the peak war years in Iraq and Afghanistan, the US Army and US Marine Corps, the 2 services with the largest concentration of ground combat forces, experienced a significant increase in suicides,” the commentators wrote. “For the first time in decades, suicide rates surpassed civilian levels, and they have remained elevated since. This change precipitated considerable research by several teams to understand the causal factors, including the more than $65 million Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS), a population-based epidemiological study to identify “actionable recommendations to reduce Army suicides.”

The editorial pointed out, however, that the research has reached contradictory conclusions on key risk factors, such as the association of deployment with suicide. “The Army STARRS effort was the most prolific but generated the harshest criticism for its core scientific assumptions, methods, conclusions and lack of actionable relevance,” the editorial noted. “To date, none of these studies have been able to definitively answer the overarching question of why suicide rates rose so sharply in Army and Marine personnel but not in Air Force and Navy personnel.”

The commentators suggested that this study includes “actionable information, raising tantalizing questions about the influence of military social structure and leadership on suicide risk factors as well as the potential for contagion of suicidal behaviors within Army units.”

  1. Ursano RJ, Kessler RC, Naifeh JA, Herberman Mash H, Fullerton CS, Bliese PD, Zaslavsky AM, Ng THH, Aliaga PA, Wynn GH, Dinh HM, McCarroll JE, Sampson NA, Kao  TC, Schoenbaum M, Heeringa SG, Stein MB; Army Study to Assess Risk and Resilience in Servicemembers (STARRS) Collaborators. Risk of Suicide Attempt Among Soldiers in Army Units With a History of Suicide Attempts. JAMA Psychiatry. 2017 Jul 26. doi: 10.1001/jamapsychiatry.2017.1925. [Epub ahead of print] PubMed PMID: 28746705.
  2. Hoge CW, Ivany CG, Adler AB. Suicidal Behaviors Within Army Units: Contagion and Implications for Public Health Interventions. JAMA Psychiatry. 2017 Jul 26. doi: 10.1001/jamapsychiatry.2017.1908. [Epub ahead of print] PubMed PMID:28746711.