Three new studies published Monday show that American soldiers suffer from mental disorders and suicide risks at rates comparable to or even higher than civilian populations.

The studies used data from Army Study to Assess Risk and Resilience in Service members (Army STARRS), which involves nearly 5,500 soldiers, according to HealthDay.

 "These studies provide knowledge on suicide risk and potentially protective factors in a military population that can also help us better understand how to prevent suicide in the public at large," said National Institute of Mental Health (NIMH) Director, Thomas R. Insel, M.D., in a news release.

The first study article led by Michael Schoenbaum of U.S. National Institute of Mental Health showed that suicide rates in army personnel increased between 2004 and 2009. Suicide risk was highest in male soldiers and those who had been recently demoted.

Matthew Nock, Ph.D., at Harvard University, Cambridge, Mass., and colleagues conducted the second study. They found that nearly half of the people in the study reported that they had attempted suicide before enlistment.

In the last study, Ronald C. Kessler, Ph.D., at Harvard Medical School, Boston, Mass, found that rates of common mental disorders were higher in army than in general population. Attention deficit hyperactivity disorder (ADHD), intermittent explosive disorder and substance abuse rates were higher in the army. About 85 percent of the participants with mental disorders said that the problems began before they joined the army.

"Some of the differences in disorder rates are truly remarkable," said Ronald Kessler, McNeil Family Professor of Health Care Policy at Harvard Medical School and senior author of the paper on mental disorder prevalence, according to a news release. "The rate of major depression is 5 times as high among soldiers as civilians, intermittent explosive disorder 6 times as high, and PTSD nearly 15 times as high."

The study is published in the journal JAMA Psychiatry.               

According to NIH Medline Plus, soldiers and those exposed to war are at high risk of developing Post Traumatic Stress Disorder.