A look at the medical records of Civil War soldiers suggests post-traumatic stress disorder existed back then, too, according to a study.

The researchers found that veterans who saw more death in battle had higher rates of postwar illness. Younger soldiers, including boys as young as 9, were more likely than older ones to suffer mental and physical problems after the war.

"Increased war trauma leads to increased physical and mental illness," said study co-author Roxane Cohen Silver of the University of California at Irvine. "That message can be applied to wars around the globe."

The findings, published in the February issue of Archives of General Psychiatry, were drawn from pension records on more than 15,000 Union Army veterans. The researchers examined the records, which included doctors' reports of illnesses, to find signs of cardiac, gastrointestinal and mental health problems.

Warring soldiers have carried home psychological scars for centuries. In American wars, the phenomenon has been called shell shock, combat fatigue and post-Vietnam syndrome. Medical authorities first accepted PTSD as a distinct psychiatric condition in 1980 at the urging of Vietnam veterans and their doctors.

In an editorial accompanying the new study, Dr. Roger Pitman of Harvard Medical School said the findings "should lay to rest the notion that there was something psychiatrically unique about the Vietnam Conflict or about what used to be called 'post-Vietnam syndrome.'"

In PTSD, stress hormones like adrenaline scorch a painful event deep into long-term memory, scientists believe. People get edgy, fearful and prone to nightmares or flashbacks.

The study relied on a database managed by the University of Chicago.

Eric T. Dean, author of "Shook over Hell: Post-Traumatic Stress, Vietnam, and the Civil War," used the same records in his research. He said he is skeptical the 19th-century medical records could be made standard enough for the researchers' statistical analysis to be valid.

He also questioned relying on the diagnoses of doctors from the 1800s.

"This is a heroic effort," Dean said. "I just think it's a stretch. Beyond proving war is hell, I just question their nuanced conclusions."