Suicides among active duty soldiers hit a record high last year for the second year in a row, the US Army reported Thursday, acknowledging that stress on the war-time force was a major factor.
The number of soldiers who took their lives in 2008 rose to as many as 143 from 115 the previous year, the army said.
Among the deaths, 128 have been confirmed suicides and 15 are still being investigated for a determination, said Lieutenant Michelle Martin-Hing, adding that on average "90 percent of unconfirmed go on to be confirmed.
The total has climbed in each of the past four years as the wars in Iraq and Afghanistan have intensified, according to the army.
Why do the numbers continue to go up? asked Army Secretary Pete Geren. We do not know.
Army officials said no single factor explained the increased incidence of suicides.
But General Peter Chiarelli, vice chief of the army, tied the rise to the lengthened combat deployments and high tempo of operations that have strained soldiers and their families.
There is no doubt in my mind that stress is a factor in the trend we are seeing, he said.
Army statistics released Thursday found that 30 percent of those who committed suicide last year were deployed at the time of their death, and of those more than three quarters were on their first deployment.
About 35 percent had never been deployed before; another 35 percent killed themselves after being deployed, in most cases more than a year after returning to their home bases.
Last year's suicide rate among active duty soldiers rose to 20.2 per 100,000, surpassing a demographically adjusted national suicide rate of 19.5 per 100,000 in 2005, the latest year on record.
The army has responded to the growing problem with more suicide prevention programs, efforts to screen soldiers for mental health problems, and campaigns to reduce the stigma that prevents soldiers from seeking treatment.
But officials indicated it was unclear how well they were working.
Chiarelli announced that units throughout the army will undergo special training sessions beginning February 15 to teach soldiers what to do if they see behaviors in themselves or their friends that could lead to suicide.
It also has enlisted the National Institute of Mental Health to do a long-study of factors affecting soldiers' mental health, and identify ways to decrease the incidence of suicides.