New research suggests that military veterans suffering from both PTSD and depression are at substantially increased risk of having suicidal thoughts.

The study, published in the journal Psychiatry Research, is the first to report tremendously high rates of suicidal ideation among those with co-occurring PTSD and depression.

“It has been well-established that veterans are at increased risk for developing PTSD and depression, and that those suffering from these conditions are more likely to think about, attempt, and complete suicide. As such, it is critical that researchers and care-providers identify anything we can use to target and treat them,” said study author Melanie B. Arenson of the San Francisco VA Medical Center and University of California.

For their study, the researchers evaluated 746 veterans at two Department of Veterans Affairs sites in the San Francisco Bay Area.

A little more than half of the participants served in the Vietnam era. The study also included veterans who served during World War II, the Korean War, the Gulf War, the Iraq War, and the War in Afghanistan.

“In this study, nearly 50% of veterans who had PTSD and depression at the same time endorsed thoughts that they would be better off dead or hurting themselves in some way within the previous two weeks, regardless of when they served, which means their trauma could be decades old,” Arenson told PsyPost.

“These rates are in comparison to 34% of those with depression alone, 11% of those with PTSD alone, and only 2% of those with neither disorder, suggesting that the effects of PTSD and depression on suicidal ideation are additive. These veterans represent a high risk group that can benefit from suicide prevention efforts.”

The study controlled for potentially confounding variables like demographic factors, symptom severity, anger, hostility, anxiety, alcohol use, optimism and social support. But the study — like all research — has some limitations.

“Perhaps the most substantial one being that our data was all cross-sectional (e.g. collected at the same time), so we cannot show what is leading to what: PTSD could lead to depression which could lead to suicidal thoughts, but it’s also possible that depression increases the risk of developing PTSD, and those together lead to suicidal thoughts,” Arenson explained.

“More research is needed to tease causal links apart. Additionally, this project purposefully over-recruited veterans who had PTSD, and therefore the rates of PTSD and depression we report are likely not representative of veterans overall.”

The study, “Posttraumatic stress disorder, depression, and suicidal ideation in veterans: Results from the mind your heart study“, was authored by Melanie B. Arenson, Mary A. Whooley, Thomas C. Neylan, Shira Maguen, Thomas J. Metzler, and Beth E. Cohen.