Nearly one in five students in the first two years of medical school were identified as alcohol abusers by a Chicago study, and the alcohol abusers got better grades than their classmates.

Researchers, cautioning that it is "unlikely" that alcohol abuse aids learning, offered two other possible explanations for the superior academic performance of the heavy drinkers.

One is that only the most academically capable of undergraduate alcohol abusers -- the ones who can compensate for their drinking habit -- get into medical school. The other is that hard-working and academically successful medical students may "feel they deserve a mechanism like drinking" to dispel the pressure and tension of medical school.

The study, by researchers at Rush-Presbyterian-St. Luke's Medical Center in Chicago, was reported in the Journal of the American Medical Association. Students in one class at a Midwestern medical school were surveyed six times during their four years in medical school and were divided each time into five categories -- abstainers and very light, light, moderate or heavy drinkers.

The study found that 11 percent of the students were "excessive drinkers" -- 18 or more drinks a week for men and 13 or more for women -- for at least six months of their medical education, and 18 percent were "alcohol abusers."

Alcohol consumption by women remained fairly consistent during the first three years in medical school, then declined in the fourth year. Men tended to drink more -- a median of about four to six drinks per week -- in the first two years -- but cut back to near the women's rate in the last two years because of "the current demands of medical school and the impending demands of physicianhood."

Because of the academic success of many alcohol abusers, researchers worry that abusers "may discount or ignore warnings about the academic or professional hazards of alcohol use and abuse" and may even see their drinking as a "tension-release valve" that contributes to their success."

An accompanying report in the journal's same issue, which was devoted to drug and alcohol abuse in doctors, concluded that mainstream medical education "has virtually ignored alcohol and other drug abuse as a major concern until relatively recently."