New York - A new study suggests that a tendency toward delinquency or living in a neighbourhood where drugs are readily available are just as important in determining whether a young person will abuse marijuana as whether or not he tries cigarettes or alcohol first.
The findings call into question the "gateway" hypothesis - that is, that youths at risk of drug abuse progress from using alcohol and cigarettes to illegal "soft" drugs like marijuana to "hard" drugs like cocaine and heroin, Dr Ralph Tarter of the University of Pittsburgh School of Pharmacy and colleagues write in the American Journal of Psychiatry.
Instead, Tarter and his team say their findings support the common liability model, which proposes that factors such as behavioural deviancy and "genetic risk" can predispose a person to abusing any type of drug, illegal or otherwise.
Based on this model, they note, the best way to protect kids from becoming drug abusers is to cope with conduct problems early, before the vulnerable adolescent years.
Tarter and associates followed 224 boys from about age 10 to 12 until they reached the age of 22. Ninety-nine of the boys only smoked cigarettes or drank alcohol, 97 used these "legal drugs" before trying marijuana, and 28 tried pot before taking up drinking and smoking.
The boys who had followed the traditional "gateway" path were no more likely to develop alcohol or marijuana abuse problems than those who went in the reverse direction, the researchers found.
Living in a poor-quality neighbourhood was the single factor that predisposed youths to marijuana use. For youths who did conform to the gateway path, delinquency was more important than previous legal drug use in determining whether they would wind up using marijuana.
Based on this and other research, Tarter and his colleagues write, "in effect, the greater the deviancy, the more likely an individual is to use an illegal drug. These findings underscore the need to prevent conduct problems in early childhood to diminish the risk of later illicit drug use".
SOURCE: American Journal of Psychiatry, December 2006.