Researchers at Harvard University looked at students on 116 campuses in 39 states last year - repeating a survey they had done four years previously. They found that, if anything, things had got worse.

Of 14,521 students who completed a questionnaire, almost a quarter (22.5%) had engaged in unplanned sex while under the influence of alcohol and 35.8% drove vehicles.

The problem often involves drinking by students under the legal age of 21. Often the heavy drinking had started when they were still in high school.

One in five was a frequent binge drinker - defined as having at least five drinks in a row for men, or four drinks in a row for women, three times or more in the two weeks before the survey.

Drinking culture

The great majority of those living in fraternity or sorority houses - four out of five - were binge drinkers.

"There has been a very small drop in binge drinking between 1993 and 1997, due mainly to an increase of students who do not drink at all," said Dr Wechsler.

"However, this has been more than offset by the increased intensity of drinking among those who drink: more drinking to get drunk, more frequent drunkenness and more alcohol-related problems such as drinking and driving.

"Despite highly publicised tragedies and continuing examinations of college alcohol policies, the data indicates that, at the national level thus far, the extent and nature of binge drinking has not changed."

Frequent binge drinkers were at least eight times as likely to miss a class, fall behind in their schoolwork, experience blackouts, become injured, or damage property.

The sort of student most likely to binge drink is male, white, 23 or younger and never married.

"If colleges are to have an impact on their alcohol problems, they must drastically change this way of life," said Dr Wechsler.