A study of drug use among young men suggests that those who used marijuana before trying alcohol or tobacco were about as likely to develop an addiction problem as those who drank or smoked before using marijuana, according to researchers who say the findings run counter to the "gateway" theory underlying much of U.S. drug policy.

The Pittsburgh Post-Gazette reported Dec. 5 that researchers from the University of Pittsburgh School of Pharmacy found that about a quarter of the 200 young men studied used marijuana before trying alcohol or tobacco. "This is actually quite novel, this idea," said lead researcher Ralph E. Tarter. "It runs counter to about six decades of current drug policy in the country, where we believe that if we can't stop kids from using marijuana, then they're going to go on and become addicts to hard drugs."

Neil Capretto, medical director of the Gateway Rehabilitation Center in Aliquippa, Pa., said some addicted patients' first drug was heroin, not alcohol or marijuana. He said the study "really shows the complex nature of addiction. What they're showing here is what we've been seeing in practice for years."

Capretto added that most people who use marijuana never go on to use harder drugs. "If we could push a button and all the marijuana would go away, by no means will that stop the drug problem in this country," he said.

The researchers did find, however, that marijuana users tended to have less parental supervision, live in neighborhoods where the drug was easily available, and were more apt to be behaviorally deviant, less involved in school, and to hang out with people that their parents didn't like.

The study, funded by the National Institute on Drug Abuse, was published in the December 2006 issue of the American Journal of Psychiatry.