Cannabis (drug) - Gateway Drug Theory

Gateway Drug Theory

Since the 1950s, United States drug policies have been guided by the assumption that trying cannabis increases the probability that users will eventually use "harder" drugs. This hypothesis has been one of the central pillars of anti-cannabis drug policy in the United States, though the validity and implications of this hypothesis are hotly debated. Studies have shown that tobacco smoking is a better predictor of concurrent illicit hard drug use than smoking cannabis.

No widely accepted study has ever demonstrated a cause-and-effect relationship between the use of cannabis and the later use of harder drugs like heroin and cocaine. However, the prevalence of tobacco cigarette advertising and the practice of mixing tobacco and cannabis together in a single large joint, common in Europe, are believed to be cofactors in promoting nicotine dependency among young people trying cannabis.

A 2005 comprehensive review of the literature on the cannabis gateway hypothesis found that pre-existing traits may predispose users to addiction in general, the availability of multiple drugs in a given setting confounds predictive patterns in their usage, and drug sub-cultures are more influential than cannabis itself. The study called for further research on "social context, individual characteristics, and drug effects" to discover the actual relationships between cannabis and the use of other drugs.

Some studies state that while there is no proof for this gateway hypothesis, young cannabis users should still be considered as a risk group for intervention programs. Other findings indicate that hard drug users are likely to be "poly-drug" users, and that interventions must address the use of multiple drugs instead of a single hard drug.

Another gateway hypothesis is that a gateway effect may be detected as a result of the "common factors" involved with using any illegal drug. Because of its illegal status, cannabis users are more likely to be in situations which allow them to become acquainted with people who use and sell other illegal drugs. By this argument, some studies have shown that alcohol and tobacco may be regarded as gateway drugs. However, a more parsimonious explanation could be that cannabis is simply more readily available (and at an earlier age) than illegal hard drugs, and alcohol/tobacco are in turn easier to obtain earlier than cannabis (though the reverse may be true in some areas), thus leading to the "gateway sequence" in those people who are most likely to experiment with any drug offered.

A 2010 study published in the Journal of Health and Social Behavior found that the main factors in users moving on to other drugs were age, wealth, unemployment status, and psychological stress. The study found there is no "gateway theory" and that drug use is more closely tied to a person's life situation, although cannabis users are more likely to use other drugs.