American soldiers who served in Vietnam suffer from more depression, anxiety and alcohol abuse than do other GIs, but medical examinations reveal no physical indications of exposure to Agent Orange, a herbicide used widely during the Vietnam War.

Those are among the findings of the Vietnam Experience Study, a federal report prepared for release Thursday at a hearing before a Senate committee.The study, conducted by the Centers for Disease Control and released for publication in the Journal of the American Medical Association, also showed that Vietnam veterans have a greater hearing loss and a measurably lower sperm count.

CDC based its findings on telephone interviews with 7,924 GIs who served in Vietnam and 7,364 veterans who served elsewhere. Those interviewed were selected randomly from enlisted men who entered the Army from 1965 to 1971. A subsample of 2,490 Vietnam veterans and 1,972 other soldiers also underwent extensive physical examinations as part of the study.

Vietnam veterans were almost twice as likely (19.6 percent to 11.1 percent) to report that they had health problems. Yet, when physicians who did not know the military history of the two groups examined the former soldiers, they could detect few medical differences between the Vietnam veterans and the others.

The study said the difference between what the Vietnam veterans reported and what was found in examination may be the result of increased stress.

"Vietnam veterans may have reported more symptoms and past medical conditions because they experienced more stress than did non-Vietnam veterans," said the study. Vietnam veterans also showed more anxiety and depression in a battery of psychological tests.

"Stress can produce anxiety, depression and a variety of somatic (physical) symptoms," the study said.

The Vietnam veterans are more likely to experience psychological problems, the study said. About 14 percent of the Viet vets are abusing alcohol, compared to 9 percent of the other group. For anxiety, the difference is 5 percent to 3 percent, and for depression, the difference is 5 percent to 2 percent.

Drug use was about the same between the groups, but the study said data suggest that more Vietnam veterans suffered drug-related deaths.

Fifteen percent of the Vietnam veterans also suffered some symptoms of combat-related post traumatic stress disorder, and 2 percent reported such symptoms the month of the interviews.

The study also said that the "perceived exposure to herbicides (a perception that in itself may lead to additional stress) is associated both with psychological problems and with self-reported adverse health conditions, but is not associated with objective measures of exposure."

Many in the Vietnam Veterans of America organization have blamed health problems on exposure during the war in Southeast Asia to Agent Orange, a herbicide used to thin vegetation in dense jungle combat areas. Use of Agent Orange was discontinued after it was determined that it contained dioxin, a potent cancer-causing chemical.