More American soldiers took their own lives in 2012 than were killed in combat, according to new statistics just released by the Department of Defense.

It said that 482 service members killed themselves last year. By comparison, there were only 310 combat-related deaths, which is 64 percent of the suicide rate.

Again by comparison, there were 301 active-duty suicides in 2011, 205 in 2010, and 309 in 2009 – the year the DoD launched its anti-suicide initiative – and 268 in 2008.

The numbers are shocking … but also deeply puzzling. They suggest that personal factors are more important than combat-related deployments; that the vast majority of suicides occur at home, not on a battlefield; and that the majority of deaths are among Army and Marine Corps personnel, not among the National or the Reservists.

The 2012 DoD Suicide Event Report isn’t available yet, but the 2011 report gives these statistics:

A whopping 89 percent of the deaths were regular service members. Only 7 percent were National Guard personnel and 4 percent were Reservists.

Only 10 percent of the suicides occurred during deployment. The DoD report said that 45 percent of the decedents lived in homes or apartments near their bases, while 26 percent lived on base.

Most of the suicide victims had never been deployed. Only about 47 percent had served in Iraq/Afghanistan, 15 percent had direct combat experience, and only 8 percent had a history of multiple deployments.

That’s a shock because most people link combat and suicide. “That is the storyline that we have created in our society because it’s a simple storyline and it intuitively makes sense,” Craig Bryan, associate director of the National Center of Veterans’ Studies at the University of Utah, told PRI’s The World. “The problem is that the data doesn’t support the notion that it is as simple as combat leads directly to suicide risk.”

Instead, Bryan believes the culprit is increased stress. “Life in the military these days is stressful, whether you’re in a combat zone or not,” says Bryan, who has nearly completed a three-year study of military suicide. “We’re increasingly asking our military personnel to do more with less.… And even when you’re here in the United States, even if you’re not in a combat zone, things aren’t necessarily easy.”

Even more stressful would be a pending deployment.

Some have raised questions about the prevalence of pharmaceuticals among our troops, but most of the service members who took their own lives (55 percent) had no history of a behavioral health disorder. Nearly 20 percent had mood disorders, primarily major depression. Another 16 percent had anxiety disorders, primarily post-traumatic stress disorder.

Instead, the 2011 DoD Suicide Event Report found that death rates for divorced service members were 55 percent higher than for married service members. It said that 47 percent of the decedents had a history of a failed marriage or intimate relationship, with more than half of them experiencing breakups within a month before their deaths.

Legal problems were also common. More than 18 percent were facing Article 15 judicial proceedings, and another 13 percent faced civil legal problems. More than 21 percent had lost their jobs or been demoted.

Firearms were the most frequent weapon of choice (60 percent), and nearly half killed themselves with their own weapons. Another 20 percent died of hanging.

Finally, only 13 percent had a prior history of self-injurious behavior, and nearly 74 percent of the service members did not communicate their intentions to others. If they did, it was most often to family members.

So how do we keep these guys and gals (only 5 percent of the suicide victims were female) from taking their own lives? That’ll be the subject of my next column.