The Science Is Clear: Marijuana Is Not A Gateway Drug

Via: Soru Epotok | Shutterstock


by Paul Armentano

on February 15, 2016

Persistent allegations by marijuana-law reform opponents that cannabis is a ‘gateway drug’ are not only woefully out of step with public opinion, but they are also equally out of touch with the available evidence.



In reality, scientific consensus has long dismissed the notion that cannabis exposure uniquely primes the brain in a way that influences a subject toward experimentation with other illicit substances, such as cocaine, PCP, or heroin. “There is no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other drugs,” determined investigators with the National Academy of Sciences, Institute of Medicine concluded nearly two decades ago in their report, “Marijuana and Medicine: Assessing the Science Base.” Shortly thereafter, a report issued by the RAND Corporation, entitled “Reassessing the Marijuana Gateway Effect,” affirmed, “[M]arijuana has no causal influence over hard drug initiation.” The authors concluded: “While the gateway theory has enjoyed popular acceptance, scientists have always had their doubts. Our study shows that these doubts are justified.”

In fact, despite the recent rise in adults’ consumption of marijuana, nationwide use of most other illicit substances, particularly cocaine, has fallen dramatically. Moreover, surveys of legal cannabis consumers consistently report that they often substitute pot in place of other psychoactive substances, specifically alcohol and prescription pharmaceuticals like opioids — behavior that indicates that the herb is utilized more often than not as an ‘exit’ drug rather than as a gateway to substance abuse.

States that permit patient use and access to medicinal marijuana report lower rates of mortality. Via: JAMA Network.

States that permit patient use and access to medicinal marijuana report lower rates of mortality. Via: JAMA Network.

Recent studies further show that cannabis is associated with more favorable outcomes among opioid-dependent individuals seeking outpatient treatment. Additionally, states that permit patient use and access to medicinal marijuana report lower rates of opiate abuse and mortality compared to states that continue to prohibit the plant. (By contrast, U.S. government statistics find a correlation between the public’s increased use of prescription opiates and rising rates of heroin, the latter of which some experts now contend is being fueled by the former.)

As for the longstanding contention that cannabis use sequentially precedes subjects’ use of other intoxicants, newly published research contradicts this claim as well. Writing last month in the Journal of School Health, investigators at Texas A&M University and the University of Florida, reported that the use of alcohol and tobacco typically precedes cannabis exposure in polydrug consuming subjects. The study, entitled “Prioritizing alcohol prevention: Establishing alcohol as a gateway drug and linking age of first drink with illicit drug use,” concludes, “[A]lcohol was the most widely used substance among respondents, initiated earliest, and also the first substance most commonly used in the progression of substance use.”



Similarly, the results of a new French study published in the journal Addictive Behaviors reports that people are four times more likely to progress from tobacco to weed than they are likely to try marijuana first and tobacco second. Investigators further determined that among those subjects who moved from cigarettes to cannabis, fewer than four percent ever went on to try another illicit substance. This finding is even acknowledged by the U.S. National Institute on Drug Abuse, which concedes, “[M]ost people who use marijuana do not go on to use other, ‘harder’ substances.”

But what about those minority of cannabis users who do go on to eventually use other illicit drugs? Is the pot to blame? Not likely. In fact, experts generally believe that the key variable in this equation is consumers’ interaction with dealers of other drugs, not the use of pot itself. As acknowledged by the Netherlands Institute of Mental Health and Addiction:

“As for a possible switch from cannabis to hard drugs, it is clear that the pharmacological properties of cannabis are irrelevant in this respect. There is no physically determined tendency towards switching from marijuana to harder substances. Social factors, however, do appear to play a role. The more users become integrated in an environment (‘subculture’) where, apart from cannabis, hard drugs can also be obtained, the greater the chance that they may switch to hard drugs. Separation of the drug markets is therefore essential.”

Or, to put it another way: If more jurisdictions ultimately legalize and regulate marijuana in a manner similar to alcohol — thereby allowing its sale to be governed by licensed, state-authorized distributors rather than by criminal entrepreneurs and pushers of various other, hard drugs — the likely result is that fewer marijuana users will progress to other illicit drugs.


Paul Armentano is the deputy director of NORML (National Organization for the Reform of Marijuana Laws) and serves as a senior policy advisor for Freedom Leaf, Inc. He is the co-author of the book, Marijuana Is Safer: So Why Are We Driving People to Drink? (Chelsea Green, 2013) and the author of the book, The Citizen’s Guide to State-By-State Marijuana Laws (Whitman Books, 2015).