By Linda Carroll

(Reuters Health) – Nearly half of deployed soldiers thinking about suicide show no obvious signs that would help mental health professionals identify them, a new study finds.

Researchers poring through data on almost 4,000 soldiers serving in Afghanistan in 2012 found that 40% of those who said they had contemplated suicide in the past 30 days had not been diagnosed with a major mental health problem and did not show any other signs that would help health providers to identify them as being at risk, according to the report in JAMA Network Open.

“These soldiers wouldn’t have been picked up if they were just screened for mental health disorders,” said coauthor Dr. Robert Ursano, director of The Center for the Study of Traumatic Stress at the Uniformed Services University.

Identifying which soldiers are thinking about suicide, known as suicidal ideation, is very important, Ursano said.

“Of those who have suicidal ideation, 6% attempted suicide in the next 18 months,” he explained. “Among those who didn’t, the suicide rate was less than 1% over the same period of time.”

As for the other 60% who reported recent suicidal ideation, there were predictors, Ursano said. The biggest was a history of major depressive disorder. Also important was a history of non-combat related trauma, which could include being in a motor vehicle accident, being sexually assaulted, being in a tornado, being mugged, Ursano added.

Combat trauma wasn’t predictive, Ursano said. “In the theater, they’re all being exposed to combat trauma,” he explained. “So it didn’t distinguish who was at risk.”

To take a closer look at what factors might help healthcare providers figure out who might be most at risk, Ursano and his colleagues turned to a questionnaire that had been filled out in July 2012 by soldiers deployed to Afghanistan.

The researchers focused on a sample of 3,957 who were representative of the 87,032 serving in Afghanistan at the time. The researchers also had information from military administrative records on gender, age, race/ethnicity, education and marital status.

Also in the analysis were lifetime and past 12-month exposures to traumatic and stressful events.

The soldiers were asked about combat-related traumas, such as whether they had taken enemy fire, had been wounded or if a unit member had been wounded or killed. They were asked about lifetime stressors, including serious physical assault, sexual assault or rape, murder of a close friend or relative and involvement in disasters.

Overall, 11.7% of the soldiers reported ever having suicidal ideation during their lives; 3% reported suicidal ideation in the past year; and 1.9% reported suicidal ideation in the past 30 days.

When the researchers analyzed factors that could affect the likelihood a soldier might start thinking about suicide, they found several: being white raised the risk by threefold, experiencing noncombat trauma raised the risk twofold, major depression prior to the last 30 days resulted in a nearly five-fold risk increase and major depression in the past 30 days produced a 31-fold increase in risk.

Among the 85 soldiers who had thought about suicide in the past 30 days, five (6%) attempted suicide in the 18 months after filling out the questionnaire. Among the 3,872 soldiers who had not experienced suicidal ideation, six (0.14%) attempted suicide.

“This is a very important study,” said Nadine Melhem, director for the program of neurobiology of stress response and suicide at the University of Pittsburgh, who wasn’t involved in the study. “It suggests we can look for predictors before deployment to see if they are at risk of suicidal ideation in order to help them.”

The study shows that suicidal ideation in soldiers is triggered by similar factors to those leading civilians to think about suicide, said Dr. Paul Nestadt, an assistant professor in the department of psychiatry and behavioral sciences at the Johns Hopkins School of Medicine in Baltimore who also wasn’t involved in the research.

What the study can’t say is who is likely to attempt suicide in the next 30 days, Nestadt noted. “That is what I want to know,” he added.

SOURCE: JAMA Network Open, online January 29, 2020.