Is marijuana a gateway drug? A state assembly hopeful says so

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The Republican challenger for the 81st District Assembly seat reiterated a decades-old claim about marijuana at a campaign event on Sept. 8.

David Moore, currently a Sauk County Supervisor, accused his opponent, Rep. Dave Considine, D-Baraboo, of trying to make Wisconsin the “Colorado of the Midwest.” A local paper quoted Moore as saying marijuana is a “gateway” to harder drugs.

The Observatory decided to check if current research on marijuana’s relationship with more dangerous drugs is settled science or still up for debate.

In an email interview former president of the Wisconsin Society of Addiction Medicine, Dr. Mike Miller said the term “gateway” means if you did A first, you’re more likely to do B.

In Moore’s claim, A is marijuana B is more dangerous drugs.

This claim isn’t new. The theory that marijuana is a gateway drug has been the subject of research, and debate, going back decades.

According to a 2015 article in Substance Use & Misuse, “[Gateway drug] hypotheses have often played an important role in developing drug use policy.”

Recent events, including the national rise in heroin and opioid deaths, have brought the debate about marijuana and its legalization to the forefront.

The National Institute on Drug Abuse (NIDA), a federal research institute affiliated with the U.S. Department of Health and Human Services, cites a number of studies which support the gateway hypothesis as of August 2016.

For example, a 2016 study using longitudinal data from the National Epidemiological Study of Alcohol Use and Related Disorders found adults reporting marijuana use were at increased risk of developing an alcohol use disorder within three years.

But Moore isn’t just claiming marijuana use leads to other substance use, he’s saying it leads to usage of more dangerous drugs, such as methamphetamine, cocaine and heroin.

NIDA notes, “The majority of people who use marijuana do not go on to use other, ‘harder’ substances,” on its website.

But, according to Miller, this fact does not negate the gateway drug concept.

“Addiction is more interesting and nuanced than an onramp concept,” Miller said. He said proving marijuana use causes abuse of more dangerous drugs is hard. But there is an association, Miller said, adding that those who “use [marijuana] are more likely to use other drugs than those who never tried pot.”

A 2015 infographic from the Centers for Disease Control and Prevention showed that people with a marijuana addiction are three times more likely to become addicted to heroin. The CDC did not, however, assert a causal relationship between usage of the two drugs.

NIDA’s inaugural director Dr. Robert L. DuPont – who popularized the term gateway drug in the 1980s – touted this view in his contribution to a New York Times op-ed debate on the marijuana gateway theory earlier this year.

Writing in opposition to the legalization of marijuana, DuPont asserts that the drug is positively correlated with alcohol, cocaine, heroin and methamphetamine use.

DuPont ultimately argues increasing access to marijuana will harm public health efforts.

But others are less convinced.

The same New York Times debate featured an op-ed from Ethan Nadelmann, who has published scholarly research on drug policy. Nadelmann is also the founder and executive director of the Drug Policy Alliance – an advocacy group dedicated to enacting liberal-leaning drug law reform.

According to Nadelmann, “The gateway theory can be summarized as an ounce of truth embedded in a pound of bull.”

Nadelmann goes on to cite a 2014 study suggesting the increase in access to medical marijuana across the United States is “strongly associated” with fewer people dying from drug overdoses, including heroin.

He also cites a 2000 study in which the National Academy of Sciences’ Institute of Medicine said, “There is no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other illicit drugs.”

Lastly, NIDA has said more research is needed.

“An alternative to the gateway-drug hypothesis is that people who are more vulnerable to drug-taking are simply more likely to start with readily available substances like marijuana, tobacco, or alcohol, and their subsequent social interactions with other substance users increases their chances of trying other drugs,” the federal research institute said.

The rating

Moore’s assertion that marijuana is a gateway drug that leads to use of more dangerous substances is not necessarily off-base and there is evidence to support it. But, even after decades of research, the theory that marijuana use leads to more dangerous dangerous drugs remains unproven.

Therefore, this claim is rated unobservable.


Madeline Sweitzer

“Republicans lay out agendas,” by Tim Damos, Baraboo News Republic, September 9, 2016
Email interview with Dr. Mike Miller, Oct. 4, 2016
“Ready for Retirement: The Gateway Drug Hypothesis,” by John Kleinig, PhD, Substance Use & Misuse, 2015.
“Is marijuana a gateway drug?” National Institute on Drug Abuse, last updated August 2016.
“Is cannabis use associated with an increased risk of onset and persistence of alcohol use disorders? A three-year prospective study among adults in the United States,” by Weinberger AH, Platt J, Goodwin RD, Drug & Alcohol Dependence, April 1, 2016 Vol. 161, pgs. 363–367.
“Marijuana Has Proven to Be a Gateway Drug,” by Robert L. DuPont, The New York Times, April 26, 2016.
“Today’s Heroin Epidemic Infographics,” Centers for Disease Control and Prevention, July 7, 2015.
“Dr. Robert L. DuPont,” National Rx Drug Abuse & Heroin Summit, 2016.
“Fears of Marijuana’s Gateway Effect Vastly Exceed the Evidence,” by Ethan Nadelmann, The New York Times, April 26, 2016.
Drug Policy Alliance website.
“Medical Cannabis Laws and Opioid Analgesic Overdose Mortality in the United States, 1999-2010,” by Marcus A. Bachhuber, MD; Brendan Saloner, PhD; Chinazo O. Cunningham, MD, MS; Colleen L. Barry, PhD, MPP, JAMA Intern Med. Vol. 174, Issue 10, pg. 1668-1673, October 2014.
“Marijuana and medicine: assessing the science base: a summary of the 1999 Institute of Medicine report,” by Watson SJ, Benson JA Jr, Joy JE, Arch Gen Psychiatry Vol. 57, Issue 6, pg. 547-52, June 2000.

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