Risk Factors, Methods, and Timing of Suicide Attempts Among US Army Soldiers

Abstract

Importance: Suicide attempts in the US Army have risen in the past decade. Understanding the association between suicide attempts and deployment, as well as method and timing of suicide attempts, can assist in developing interventions.

Objective: To examine suicide attempt risk factors, methods, and timing among soldiers currently deployed, previously deployed, and never deployed at the time this study was conducted.

Design, setting, and participants: This longitudinal, retrospective cohort study of Regular Army-enlisted soldiers on active duty from 2004 through 2009 used individual-level person-month records to examine risk factors (sociodemographic, service related, and mental health), method, and time of suicide attempt by deployment status (never, currently, and previously deployed). Administrative data for the month before each of 9650 incident suicide attempts and an equal-probability sample of 153 528 control person-months for other soldiers were analyzed using a discrete-time survival framework.

Main outcomes and measures: Suicide attempts and career, mental health, and demographic predictors were obtained from administrative and medical records.

Results: Of the 9650 enlisted soldiers who attempted suicide, 86.3% were male, 68.4% were younger than 30 years, 59.8% were non-Hispanic white, 76.5% were high school educated, and 54.7% were currently married. The 40.4% of enlisted soldiers who had never been deployed (n = 12 421 294 person-months) accounted for 61.1% of enlisted soldiers who attempted suicide (n = 5894 cases). Risk among those never deployed was highest in the second month of service (103 per 100 000 person-months). Risk among soldiers on their first deployment was highest in the sixth month of deployment (25 per 100 000 person-months). For those previously deployed, risk was highest at 5 months after return (40 per 100 000 person-months). Currently and previously deployed soldiers were more likely to attempt suicide with a firearm than those never deployed (currently deployed: OR, 4.0; 95% CI, 2.9-5.6; previously deployed: OR, 2.7; 95% CI, 1.8-3.9). Across deployment status, suicide attempts were more likely among soldiers who were women (currently deployed: OR, 3.4; 95% CI, 3.0-4.0; previously deployed: OR, 1.5; 95% CI, 1.4-1.7; and never deployed: OR, 2.4; 95% CI, 2.3-2.6), in their first 2 years of service (currently deployed: OR, 1.9; 95% CI, 1.5-2.3; previously deployed: OR, 2.2; 95% CI, 1.9-2.7; and never deployed: OR, 3.1; 95% CI, 2.7-3.6), and had a recently received a mental health diagnosis in the previous month (currently deployed: OR, 29.8; 95% CI, 25.0-35.5; previously deployed: OR, 22.2; 95% CI, 20.1-24.4; and never deployed: OR, 15.0; 95% CI, 14.2-16.0). Among soldiers with 1 previous deployment, odds of a suicide attempt were higher for those who screened positive for depression or posttraumatic stress disorder after return from deployment and particularly at follow-up screening, about 4 to 6 months after deployment (depression: OR, 1.4; 95% CI, 1.1-1.9; posttraumatic stress disorder: OR, 2.4; 95% CI, 2.1-2.8).

Conclusions and relevance: Identifying the timing and risk factors for suicide attempt in soldiers requires consideration of environmental context, individual characteristics, and mental health. These factors can inform prevention efforts.

Figure 1. Suicide Attempts by Deployment Status Among Regular Army Enlisted Soldiers

The sample of enlisted soldiers (9650 soldiers who attempted suicide and 153 528 control person-months) is a subset of the total sample (193 617 person-months) from the Army Study to Assess Risk and Resilience in Service members Historical Administrative Data Study. Standardized risk estimates (soldiers who attempted suicide per 100 000 person-years) assume other predictors were at their samplewide means. Estimates were calculated based on logistic regression models that included basic sociodemographic and service-related variables (sex, age at entry into the Army, current age, race/ethnicity, education, marital status, and time in service) and also included a dummy predictor variable for calendar month and year to control for secular trends.

Figure 2. Standardized Risk of Suicide Attempt by Mental Health Diagnosis and Deployment Status Among Regular Army Enlisted Soldiers

The sample of enlisted soldiers (n = 9650 soldiers who attempted suicide and 153 528 control person-months) is a subset of the total sample (n = 193 617 person-months) from the Army Study to Assess Risk and Resilience in Service members Historical Administrative Data Study. Any mental health diagnosis includes most International Classification of Diseases, Ninth Revision, Clinical Modification codes for mental disorders (eg, major depression, bipolar disorder, anxiety disorder, and personality disorders), but excludes postconcussion syndrome and tobacco use disorder when those were the only recorded mental health diagnoses. See eTable 3 in the Supplement for a complete list of included and excluded International Classification of Diseases, Ninth Revision, Clinical Modification codes. Standardized risk estimates (soldiers who attempted suicide per 100 000 person-years) assume other predictors were at their samplewide means. Estimates were calculated based on logistic regression models that included basic sociodemographic and service-related variables (sex, age at entry into the Army, current age, race/ethnicity, education, marital status, and time in service) and also included a dummy predictor variable for calendar month and year to control for secular trends.

Figure 3. Monthly Risk of Suicide Attempt Risk by Deployment Status Among Regular Army–Enlisted Soldiers^,

The sample of enlisted soldiers (24 741 never-deployed soldiers in their first year of service; 13 833 currently deployed soldiers on their first deployment; and 38 281 previously deployed soldiers after their first deployment) is a subset of the total sample (193 617 person-months) from the Army STARRS Historical Administrative Data Study. Monthly risk based on hazard rates and linear spline models.

Figure 4. Postdeployment Depression or Posttraumatic Stress Disorder and Risk of Suicide Attempt Among Regular Army–Enlisted Soldiers With 1 Previous Deployment

The sample of 10 378 enlisted soldiers with 1 previous deployment who completed both the Postdeployment Health Assessment (early screen; 1–3 months after deployment) and Postdeployment Health Reassessment (late screen; 4–5 months after deployment) prior to their suicide attempt (cases) or sampled person-month record (controls) is a subset of the total sample (193 617 person-months) from the Army Study to Assess Risk and Resilience in Service members Historical Administrative Data Study. Odds ratios and standardized risk estimates for each diagnostic category were calculated based on logistic regression models that adjusted for the other diagnostic categories and basic sociodemographic and service-related variables (sex, age at entry into the Army, current age, race/ethnicity, education, marital status, and time in service), and which also included a dummy predictor variable for calendar month and year to control for secular trends.