(CNN) -- The record number of military suicides seen in recent years may not be directly due to extended deployments or combat experience, according to a new study. This data analysis, funded by the Department of Defense, suggests that the real reason behind the growing number of military suicides is underlying mental health issues in this population.
Their findings will be published in the next edition of the Journal of the American Medical Association.
What's causing soldiers to kill themselves at a record rate -- there were 325 confirmed or potential suicides last year among active and non-active military personnel -- are the same mental health problems that can be found in the general population, according to the study authors: depression, manic depression and alcohol abuse.
These are all problems that are fundamentally treatable at some level. But the military will have to change the way it handles soldiers with mental illness if we expect to see the number of suicides decline, according to the author of a related editorial published in the journal.
The researchers said they did this study because of the alarming increase in military suicides; in the past, some studies have shown that military personnel were less at risk for suicide than the general population.
The study authors looked at data from the Millennium Cohort Study, the largest-ever long-term study on the military.
The cohort study randomly selected samples of the military population in 2001 to look at their overall health. It checked in with these study participants every three years, regardless of whether they were active-duty or out of the service, and recorded information about their mental, behavioral and functional health.
The Millennium Cohort Study is also funded by the Department of Defense, which plans to follow the same people for the next 67 years, according to the cohort's principal investigator, Dr. Nancy Crum-Cianflone.
The authors found 646 deaths in the more than 150,000 study participants between 2001 and 2008. Of the deaths, 83 were suicides -- just less than 13%.
Those who had committed suicide generally had been deployed for fewer days in a row than other study participants; being deployed for longer than a year was actually associated with a lower risk of suicide. But military personnel who committed suicide were also more likely to be combat specialists and have pre-2001 deployment experience.
"The findings from this study are not consistent with the assumption that specific deployment-related characteristics, such as length of deployment, number of deployments or combat experiences are directly associated with increased suicide risk," the study authors wrote.
The data also showed that the majority of those who killed themselves either struggled with heavy drinking and depression or had been diagnosed with manic depression. The researchers characterized heavy drinkers as men who had more than 14 drinks per week, women who had more than seven drinks per week or binge drinkers (men who had five or more drinks or women who drank four or more in one day).
"Many people might be surprised by these results, but my colleagues and I really weren't surprised based on what we know about the people who have committed suicide," said Cynthia LeardMann, the study's lead author and a senior biostatistician with the Deployment Health Research Department at the Naval Health Research Center in San Diego. "Most suicides happen among troops who have not seen combat."
But what about post-traumatic stress disorder? The study authors looked at PTSD as a factor but found that only nine of the 83 people who committed suicide -- about 10% -- had been diagnosed with PTSD or reported experiencing symptoms of PTSD. Comparatively, 55 of the 83 reported heavy drinking.
There are limits to this study. The data were collected only through 2008, meaning the study couldn't account for the more recent time period in which military suicide rates were at their highest and conflicts overseas were still ongoing. "It is possible that the cumulative strain of multiple lengthy deployments only began to be reflected in suicide rates toward the later stages of the conflict," the study authors write.
Also, outside studies show that suicides are underreported on death certificates, and these health surveys gather data using a lot of self-reporting. There is always a chance people could down play certain mental health struggles; however, the authors argue that previous studies suggest that self-reporting screening measures are reliable with this particular population.
LeardMann thinks the results will remain consistent as the data analysis continues.
"We are not expecting to see an association with deployment and suicide risk," LeardMann said.
"That's what's so vexing about this study," said David Jobes, a professor of psychology who runs the Suicide Prevention Lab at Catholic University of America in Washington and who is not affiliated with the study but is familiar with its content.
"The results are so counterintuitive, but I think the data in this study is very solid. What it shows is, we really don't know the full story here about what is really causing the rise, because what the study describes are people who are normally at risk for suicide: They are male, bipolar, people who drink too much or depressed -- that's not unique to the military population."
The study also does not compare military suicide numbers to the civilian population. There is some evidence that the suicide rate also rose in the general U.S. population as the recession intensified, but that remains uncertain until data from the Centers for Disease Control and Prevention catch up with the military data.
Suicides in the military have been escalating since 2005, when there were 87. In 2012, there were 325. But these incidents have been difficult to study, predict and prevent, according to Dr. Charles Engle, who wrote the editorial accompanying the study. He said the results of this study provide "reassuring ways forward" since there are effective treatments available for mood disorders and misuse of alcohol.
But Engle argues that the military's "current over-reliance on outdated combat and stress models of suicide patterns" and the "long-standing military ambivalence toward the medical model of mental illness" may mean the suicide problem will continue.
The Veterans Administration has taken suicide seriously: It set up a crisis help line. It staffed medical centers with suicide coordinators. It made strides in integrating mental health services with primary care, and it has hired more than 1,000 additional mental health care professionals this year to cope with some of these issues.
Engle said leaders in the military need to abandon what he described as the unfounded notion that diagnosing soldiers with common mental illness will reduce their will to function normally and recover.
He also encourages military psychologists to enforce the same confidentiality standards that are expected when a civilian seeks help for mental illness. While in civilian life, there is an expectation of privacy for those medical and mental health records, there is no similar practice in the military. He argues that soldiers should no longer be stigmatized for seeking help and should no longer have barriers to promotion if they are in treatment.
Psychologist David Rudd (PDF) says that although this new published study is important, it is limited because it's only a snapshot of a brief period of time. While it looks at combat vs. noncombat soldiers and their risk for suicide, it fails to take into account the severity of combat exposure, he said.
Rudd is wrapping up the results of his own clinical study on the treatment of suicidal soldiers at Fort Carson, Colorado.
"We actually have some data that does link suicide risk to very severe exposure to combat," Rudd said, although his data set is not as large as this new published study's. The results of his research will go under review next month.
Rudd argues overall that the military may not be the best place for long-term psychiatric care.
Instead, Rudd suggests, there should be better mental health screening on the front end. Currently, an understanding of a soldier's mental health upon enlistment is based on self-reported surveys. But tests later on of these same soldiers often turn up mental health problems that were there long before they served in the military, he said. The study, he argued, speaks to a much larger issue.
"We as a society have a hard time accepting that war presents a persistent problem of being (in) a high-stress environment," Rudd said. "It is remarkable that the vast majority of people who go into these high-stress environments come back and do fine and move on with their lives.
"But for those who suffer from a mental disorder, these repeated high-stress situations and exposures to the intensity of combat cause psychological injuries. And while we can reduce suicide rates, there will always be vulnerable people, and I think we have a hard time accepting that."