Veterans who bore the brunt of the battle in Vietnam abused alcohol and drugs more often in later civilian life and were arrested more often than their counterparts who were not in combat or who did not serve in Vietnam.

Those are the main conclusions of an eight-year study done for the Veterans Administration by the Center for Policy Research in New York, which followed and questioned 1,340 Vietnam veterans -- 842 whites, 415 blacks and 83 Hispanics -- in eight U.S. cities and two rural communities in the South and the Midwest.

The study found that whites who experienced heavy combat had a higher arrest rate when they returned to civilian life than did blacks or Hispanics who were in heavy combat, mostly because of more drunk-driving arrests. The whites in the study also abused alcohol far more than the blacks and Hispanics did.

On the other hand, the blacks and Hispanics had a higher drug-abuse rate and were arrested more often than whites for possession and sale of dangerous drugs. The study said that black and Hispanic veterans tended to abuse a broad array of drugs, including marijuana, hashish, heroin, amphetamines, LSD and cocaine.

In its $2 million study for the VA, the research center broke down its sample into those who had experienced heavy combat, those who had served in Vietnam but did not see combat, and those who served in the armed services outside Vietnam. Of the total, 48 percent were classified in the first group, meaning they had been in firefights, been ambushed or were under steady sniper and patrol fire.

The study found that those in heavy combat were far more likely to suffer long-term stress than those who were not. Blacks in heavy combat suffered more long-term stress than did whites, it said, in part because they abused drugs more frequently and in part because they had fewer stable marriages and close friendships to support them.

A spokesman for the center identified long-term stress as suffering from dizziness, anxiety, tension, headaches, stomach trouble, loss of memory, depression, repeated nightmares and loss of control and interest.

The most striking figures were the arrest rates for those returning to civilian life after experiencing heavy combat. Twenty-four percent were arrested at least once, most for drunken driving or drug possession. Most of those arrested came from the large cities surveyed -- New York, Chicago and Los Angeles. The other cities studied were Bridgeport, Conn.; South Bend, Ind.; Columbus, Ga., and Atlanta, as well as heavily populated regions of southern Westchester County, N.Y., and the rural areas around South Bend and Columbus.

Heavy combat had its strongest effect on the drinking behavior of returning veterans. The study said that combat veterans tended to drink more with each point they had on a "Combat Scale" of 1 to 13. The sliding scale was based on the number of firefights a veteran had been in, how often he had been ambushed, how many combat patrols he had been on, and how exposed he had been to fire during combat.

The study found that the Vietnam war had a profound effect on most of the combat veterans. Many felt alienated when they returned to this country and found it hard to return to pre-war careers or to resume their education. Said the study: "Only one-quarter of Vietnam veterans believe the war had little or no effect on them. These men tend to have had little direct exposure to death and to have had remote relationships to the Vietnamese."