Anti-drug advocates who have admonished for years that marijuana is a "gateway drug" may be on to something, according to a study by Yale University School of Medicine researchers.

The Yale study, which appears online in the Journal of Adolescent Health, showed that alcohol, cigarettes and marijuana were associated with an increased likelihood of prescription drug abuse in men 18 to 25.

In women of that age, only marijuana use was linked with a higher likelihood of prescription drug abuse.

For years, researchers have looked at a connection between marijuana and hard drugs, such as cocaine and heroin, said Lynn Fiellin, the study's lead author and an associate professor of medicine at the Yale University School of Medicine.

A high school teacher and a graduate student at Northwestern University headed the Red Watch Band program, an attempt to save students from themselves.

Red Watch Band teaches students to recognize the warning signs of alcohol poisoning - vomiting; cold, clammy skin; the inability to wake up - and to call for medical help.

The program is part of a wave of college initiatives meant to quell a chronic problem – binge drinking on campus.

The percentage of college students who binge drink - defined as five drinks for men and four drinks for women in two hours - has held steady at about 40 percent for most of the past decade, consistently more than non-college students, federal surveys show. Combining alcohol with energy drinks has fueled students' ability to drink more and longer.