Marijuana as a Gateway Drug: the Causal Fallacy

Marijuana as a Gateway Drug: The Causal Fallacy

The marijuana plant, perhaps the most widely-used illicit drug in the world, was once demonized by authorities and the media. In the 1936 film Marijuana: Weed with Roots in Hell, director Dwain Esper portrayed teens smoking marijuana and then engaging in perceived evils such as nude bathing and unchaperoned partying, with one girl becoming pregnant. The film went on to further depict the characters becoming addicted to marijuana and committing serious crimes including a police shootout and kidnapping for ransom. These claims are based on the type of faulty casual analysis that has given rise to anti-marijuana myths that have endured over the years, but they are fortunately starting to abate. While the Western world has lightened up, some misconceptions persist, particularly those based on casual fallacy. An example of such a fallacy can be found in the argument that marijuana is a “gateway drug” which causes users to eventually progress to hard drugs, when that’s not actually the case.

The correlation between marijuana and other illegal substances is not in dispute, nor is the chronology in that marijuana use typically precedes other drug use. Studies show that a hard drug users’ first experience with an illicit drug is likely to be marijuana, and that nearly every hard drug user has tried marijuana at least once. Furthermore, studies also show that marijuana users are more likely to try hard drugs than non-users. But correlation and chronology doesn’t imply causation, and it’s causation that is at the crux of the “gateway drug” argument.

The reason marijuana use typically occurs before other illicit drug is because it’s readily available and accessible, especially for youth. Instead of having to venture to a store and provide photo ID as a young teens would with liquor and tobacco, they might be able to buy marijuana without having to leave school property or even their own home. Acquiring it may involve only placing a quick phone call to a drug dealer and having it delivered like a pizza. The primary reason for this is marijuana’s illegality. By outlawing marijuana it’s driven to the black market where there is no age restriction or code of ethics.
Furthermore, a marijuana dealer may also introduce customers to their harder product lines, or at least connect them with someone who can. Dealers tend to be more cautious of selling harder drugs since the penalties, if caught, are much stiffer. Once trust is gained through the sale of marijuana, they might be more comfortable progressing to more serious transactions. Because of this, the first experience people may have to illicit drugs is likely to be marijuana, putting it in the position where it appears to cause other drug use simply because of chronological order.

The lack of objective evidence showing a casual link between marijuana and hard drugs was discussed in the scientific literature as early as 1999. In the book Marijuana and Medicine: Assessing the Science Base, published by the US Institute of Medicine, researchers wrote that “because it is the most widely used illicit drug, marijuana is predictably the first illicit drug most people encounter” and that “not surprisingly, most users of other illicit drugs have used marijuana first” (Joy et al. 6). However, “there is no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other illicit drugs” (Joy et al. 6). Subsequent research has similarly been unable to establish casual links.
While most hard drug users started with marijuana, and most hard drug users have used marijuana, it’s important to note that most marijuana users don’t actually use hard drugs. If marijuana caused hard drug use we would expect the rates of marijuana use to be consistent with the rates of hard drug use. The rate of marijuana use is nearly six-times higher than the five major types of hard drugs combined, according to Canadian government statistics. Health Canada’s 2010 “Canadian Alcohol and Drug Use Monitoring Survey“ reported that 10.7% of respondents 15 years of age or older admitted to using marijuana in the past year, while only 0.7% used crack, 0.5% used speed, 0.7% used ecstasy, and 0.7% used some type of illicit hallucinogen (excluding salvia). The total reported usage for these other drugs is 1.8%, nearly one-sixth that of marijuana.

Another factor is that marijuana users tend to be more prone to using hard drugs simply because they have the personality traits conducive to substance abuse. These traits include the attitudes, feelings, responses, and behaviours that contribute to a person’s psychological makeup. In the 2002 article “Are Personality Traits Familial Risk Factors for Substance Use Disorders?” researchers explain that “longitudinal studies have implicated personality characteristics as predisposing vulnerabilities for the subsequent development of substance-related disorders” (Swendsen et al.). In this sense, marijuana and crack users have something in common; they are all willing to alter one’s mind to the chagrin of the law.
Casual fallacies abound when we humans attempt to understand the world around us. It’s tempting to conclude that causation is established because there is a correlation or chronological order of events, but that’s not a logical approach. There are a multitude of factors to consider when establishing a causal link, and this is no exception. While marijuana is correlated with hard drugs, and marijuana use typically precedes hard drug use, it does not actually cause hard drug use. Like the other fallacies before it, the “gateway drug” fallacy is yet another marijuana myth that can hopefully be put to rest.

Works Cited

Canada. Health Canada. “Canadian Alcohol and Drug Use Monitoring Survey: 2010.” Ottawa: Health Canada, n.d. Web. 16 Nov. 2011. <http://www.hc-sc.gc.ca/hc-ps/drugs-drogues/stat/_2010/summary-sommaire-eng.php>.
Joy, Janet E., et al. Marijuana and Medicine: Assessing the Science Base. Washington, DC: The National Academic Press. 1999. Print.
Marihuana: Weed with Roots in Hell! Dir. Dwain Esper. Perf. Harley Wood, Hugh McArthur, Pat Carlyle, and Paul Ellis. Roadshow Attractions Inc., 1936. Film.
Swendsen, Joel D., et al. “Are Personality Traits Familial Risk Factors for Substance Use Disorders? Results of a Controlled Family Study” The American Journal of Psychiatry 159.10 (2002): 1760-1766. Web. 18 Nov. 2011.

Cited: Canada. Health Canada. “Canadian Alcohol and Drug Use Monitoring Survey: 2010.” Ottawa: Health Canada, n.d. Web. 16 Nov. 2011. &lt;http://www.hc-sc.gc.ca/hc-ps/drugs-drogues/stat/_2010/summary-sommaire-eng.php&gt;. Joy, Janet E., et al. Marijuana and Medicine: Assessing the Science Base. Washington, DC: The National Academic Press. 1999. Print. Marihuana: Weed with Roots in Hell! Dir. Dwain Esper. Perf. Harley Wood, Hugh McArthur, Pat Carlyle, and Paul Ellis. Roadshow Attractions Inc., 1936. Film. Swendsen, Joel D., et al. “Are Personality Traits Familial Risk Factors for Substance Use Disorders? Results of a Controlled Family Study” The American Journal of Psychiatry 159.10 (2002): 1760-1766. Web. 18 Nov. 2011.