More U.S. Army soldiers die by suicide than in combat. There are a number reasons for that, but a study published on Friday in the Journal of the American Medical Association shows a strong relationship between keeping a personal firearm and suicide among soldiers.

The study, the first of its kind, looked at the histories of 135 active duty U.S. Army soldiers who committed suicide between August 1, 2011, and November 1, 2013, dates coinciding with a peak in suicides among soldiers. Shootings accounted for 55 percent of those deaths. That, by itself, might not be surprising. What is remarkable, in the words of the researchers, is that having access to a loaded gun at home, or carrying one in public, “resulted in a 4-fold increase of the odds of suicide” compared to other soldiers.

The authors point to an existing psychological theory to explain why that might be so. The interpersonal theory of suicide posits that simply a desire to commit suicide is usually not enough to convince people to take their own life. The theory argues that people who have overcome a fear of death through repeated exposure either to personal pain or fearinducing experienecs, or the pain and fear of others, are more likely to commit suicide. Another study from 2012 found that men who keep loaded weapons also exhibit a reduced fear of death.

“For soldiers on active duty, such experiences may be commonplace, and it is possible that our study has identified a subset of service personnel with an increased suicide capability and a reduced fear of death,” the authors write.

An accompanying article by Drs. Joseph A. Simonetti and Ali Rowhani-Rahbar offers clinicians advice on what to recommend to soldiers, especially those who may be grappling with suicidal thoughts. Bottom line: get guns out of your house. “The most evidence-based and conceptually sound recommendation for suicide prevention remains the same for adults with elevated suicide risk who reside in homes with firearms: removing firearms from the home is likely to offer the greatest suicide risk reduction. However, studies have not delineated to what extent adults will follow this advice,” they write.