The gateway hypothesis essentially maintains that there are progressive, sequential stages to involvement with drug use (Kandel, 2002). Drug use that usually starts with legal drugs of tobacco and alcohol progresses to marijuana, and from marijuana to illicit drugs heroin, methamphetamines and cocaine. If an individual started legal drug usage at an early age of adolescence, there is an increased risk of that individual advancing into using more dangerous and illegal drugs (Kandel, 2002). However, it does not mean that all individuals using legal drugs progress to illegal drug abuse.
There has been considerable public debate regarding marijuana’s potential as a “gateway” drug following its partial or almost full legalization in certain states in the USA. If one applies the three considerations of the gateway hypothesis namely sequencing, association and causation to marijuana, the results are not unequivocal to categorize marijuana as a gateway drug. It is reasonable to expect that a person using legal marijuana from an early age sequentially progressing to illicit drug use. In addition, the association part both in terms of social and habitual can play a significant part in progression to illegal drug abuse. However, it is not clear if causation is a major aspect of individual deteriorating into drug abuse with marijuana. In sharp contrast to alcohol use, marijuana usage rarely provokes violence or crime (Ben Amar, 2004). On the other hand, it tends to suppress aggressive behavior and may even calm the consuming individual (Ben Amar, 2004).
In summary, marijuana may not be considered as a gateway drug since it does not fulfill all the three criteria deemed important in gateway drugs such as alcohol and tobacco. However, it does fulfill some of the criteria of gateway drugs and thus can be harmful, especially if introduced into use from an early adolescent age.
Ben Amar, M. (2004). harmacology of Cannabis and Synthesis of the Analyses of the Principal Expert Committees. Drogues, 2-3, 9-60.
Kandel, D. B. (2002). Stages and pathways of drug involvement : examining the gateway hypothesis. Cambridge, UK ; New York: Cambridge University Press.