The debate around whether cannabis leads to harder drug use is a long-standing, fierce and global one. The Gateway hypothesis argues that there is a casual chain in drug-taking, where users of cannabis, considered one of the least dangerous drugs, are more likely to then go on to use “harder drugs”. But what evidence is there for this argument?
The debate around whether cannabis leads to harder drug use is a long-standing, fierce and global one. The Gateway hypothesis argues that there is a casual chain in drug-taking, where users of cannabis, considered one of the least dangerous drugs, are more likely to then go on to use “harder drugs”. But what evidence is there for this argument?
Cannabis as a Gateway Drug
The Gateway Drug Theory, first popularized in the 1980s, suggests that cannabis is likely to be used before advancing to “harder” drugs, such as opioids, cocaine and methamphetamines. Panic-inducing anti-drug commercials during the 80s and 90s constantly warned drug users of the dangers of so-called “gateway drugs”. Decades later, politicians and science researchers are still debating whether “softer gateway drugs” can cause a chain of events that lead to addiction and use of hard drugs. This is one of the main arguments against the legalisation of cannabis.
On balance, research generally supports the belief that cannabis use is a risk factor for ensuing use of “harder” illicit drugs, although many are in disagreement with this. The basis for the belief in “Gateway Drugs” is that users experience biological alterations in the brain that can make them seek more dramatic dopamine releases through stronger substances and also expose users to social groups that partake in drug-taking.
There are a large number of research studies that suggest that individuals who abuse hard substances, tried marijuana initially.
A 2014 study conducted in the International Journal of Drug Policy that used data from the National Epidemiological Survey on Alcohol and Related Conditions and examined data from 6,600 individuals who started cannabis use before using any other drug. The results showed that 44.7% of individuals with lifetime cannabis use progressed to other illicit drug use at some time in their lives.
Despite multiple studies with similar findings, there are serious issues and limitations with the research. Most importantly, these studies fail to incorporate contextual factors that have shown to have an effect on drug use such as genetics, biology and environment.
The risk of other illicit drug use in cannabis users may be higher because few people try hard drugs prior to trying cannabis and not because cannabis actually causes the use of harder drugs. Therefore, what is also important to consider is that the link between cannabis and harder drugs is that of ‘association’ and similar behavioural factors, as opposed to evidence that directly links cannabis as a ‘cause’ of harder drug use.
Cannabis as a prevention drug
Cannabis has long been vilified as a “gateway drug” but recent studies have found that marijuana might actually prevent users from moving onto “harder” drugs.
Scientists at the University of New Mexico conducted a five year study with 125 participants, all of whom were suffering from chronic pain. 83 of the participants were taking cannabis as a prescriptive pain mediator and 42 of them abstained. Results published in 2017 showed that 34 percent of the cannabis users stopped taking their medication compared to just two percent of the non-consumers. This study showed that the ability to use cannabis actually significantly reduced the need for opioid medication.
Even Recovery.org.uk, a UK drug and alcohol rehabilitation service, agrees that the link between cannabis and harder drugs is tenuous. They state that “the reality is that while some cocaine and heroin addicts did experiment with cannabis before moving on to harder drugs, the majority of those using cannabis never go on to use harder substances.”
There is an argument that the illegality of cannabis is actually the “gateway” to further drug-taking rather than the drug itself. In the UK, buying cannabis currently involves interacting with the black market and therefore are breaking the law. Individuals who have already broken the law, are more inclined to continue to commit illegal acts. Once users have interacted with dealers selling other illegal substances, they also have access to multiple drugs. The buying of harder illegal drugs may be prevented if cannabis was legal and regulated.
In recent years, there has been a shift in public opinion over cannabis with many believing that it should be legalised, or at the very least, decriminalised. Many people consider it’s various health benefits and far-reaching use in modern medicine as a strong argument that politicians and society should reconsider its status and the role it plays.
Common liability
As our understanding of drug consumption and social implications has improved, a new theory has emerged in the scientific community that has filtered into the public forum – the common liability theory. The theory suggests that certain individuals, by virtue of both nature and nurture, are more likely than others to become addicted to drugs. Addiction itself is the ‘disease’. This argument is twofold, for it also explains why many people who use so-called gateway drugs like cannabis do not become addicted, and do not move on to further substance abuse and harder drugs.
There can be a sequence in which taking cannabis can be a precursor to other drugs, but it is by no means inevitable and multiple factors contribute. In fact, friendship groups, poverty and mental illness are all stronger predictors of drug use – there are significant social causes that can influence and ultimately lead to addiction and the use of hard drugs, unrelated to the initial use of cannabis. Ultimately, association does not necessarily mean causation, casting serious doubts over the simplistic nature of the Gateway Drug Theory.
