Far fewer Vietnam veterans suffered from post-traumatic stress as a result of their wartime service than previously thought, researchers are reporting, in a finding that could have lasting consequences for the understanding of combat stress, as well as for the estimates of the mental health fallout from the Iraq war. snip The nightmares, flashbacks, and hair-trigger irritability that characterize post-traumatic reactions usually fade with time, the study found, but in 9.1 percent of the veterans — roughly a quarter million — the symptoms became chronic and disabling. Politicians have clashed over the Department of Veterans Affairs’ budget, including its $3...