In the six years after Reuben Paul Santos returned to Daly City from a combat tour in Iraq, he battled depression with poetry, violent video games and, finally, psychiatric treatment. His struggle ended last October, when he hung himself from a stairwell. He was 27.

The high suicide rate among veterans has already emerged as a major issue for the military and the families and loved ones of military personnel. But Mr. Santos’s death is part of a larger trend that has remained hidden: a surge in the number of Afghanistan and Iraq veterans who have died not just as a result of suicide, but also because of vehicle accidents, motorcycle crashes, drug overdoses or other causes after being discharged from the military.

An analysis of official death certificates on file at the State Department of Public Health reveals that more than 1,000 California veterans under 35 died between 2005 and 2008. That figure is three times higher than the number of California service members who were killed in the Iraq and Afghanistan conflicts over the same period. The Pentagon and Department of Veterans Affairs said they do not count the number of veterans who have died after leaving the military.

The figures, according to the federal Department of Veterans Affairs, legislators and experts in post-traumatic stress, underscore how veterans in Bay Area communities and across the state engage in destructive, risky and sometimes lethal behaviors.