Proponents of marijuana prohibition have long alleged that experimentation with pot acts as a “gateway” to the use and eventual abuse of other illicit substances. But the results of a just released national poll finds that most Americans no longer believe this claim to be true.

According to survey data compiled by YouGov.com, fewer than one in three US citizens agree with the statement, “the use of marijuana leads to the use of hard drugs.” Among those respondents under the age of 65, fewer than one in four agree.

Their skepticism is well warranted. In fact, science has long discredited gateway theory. More than two decades ago, the National Academy of Sciences Institute of Medicine reported “there is no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other drugs.”

More recently, Rand Corporation issued a report titled “Reassessing the Marijuana Gateway Effect.” The report affirmed that “marijuana has no causal influence over hard drug initiation.” And the authors of the report concluded:

“While the gateway theory has enjoyed popular acceptance, scientists have always had their doubts. Our study shows that these doubts are justified.”

Moreover, despite the recent rise in the adult use of marijuana in past years, nationwide use of most other illicit substances, particularly cocaine, has fallen dramatically. Further, surveys of cannabis consumers residing in jurisdictions where the plant is legally accessible find that respondents typically report decreasing their use of other drugs, such as alcohol and prescription opiates.

In 2014, Journal of the American Medical Association (JAMA) Internal Medicine reported that the enactment of statewide medicinal marijuana laws is associated with significantly lower state-level opioid overdose mortality rates, acknowledging “States with medical cannabis laws had a 24.8 percent lower mean annual opioid overdose mortality rate compared with states without medical cannabis laws.”

Separate data reported by the RAND Corporation in 2015 drew a similar conclusion, determining, “states permitting medical marijuana dispensaries experience a relative decrease in both opioid addictions and opioid overdose deaths compared to states that do not.”

Other studies indicate that pot may even play a positive role in assisting addicts kick their opioid dependency. Writing in the journal Drug and Alcohol Dependence, researchers at New York’s Columbia University reported, “[Opioid dependent] participants who smoked marijuana had less difficulty with sleep and anxiety and were more likely to remain in treatment as compared to those who were not using marijuana.” Their findings mimic those of other studies observing that cannabis often acts as an exit drug rather than as a supposed gateway.

As for the contention that polydrug users typically begin their illicit drug experimentation with weed, science refutes this claim as well. Writing in January in the Journal of School Health, investigators at Texas A&M University and the University of Florida acknowledged that the use of alcohol and tobacco typically precedes cannabis exposure in those who progress to “hard” drug abuse. And it was alcohol, the authors concluded, that was first and most widely used substance in those who progressed to harder drugs.

Of course, a small percentage of cannabis consumers do go on to use other illicit drugs. But in these instances experts generally identify ‘environmental circumstances,’ not the preceding use of cannabis, as the primary reason why some people transition to other drugs. 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, permitting marijuana sales to be regulated by licensed, state-authorized distributors rather than by criminal entrepreneurs and pushers of various other illicit drugs would likely result in fewer, not more, Americans abusing other illicit substances.

Armentano is the deputy director of NORML (the National Organization for the Reform of Marijuana Laws) and an adviser for Freedom Leaf. He is the co-author of the book "Marijuana Is Safer: So Why Are We Driving People to Drink?" (Cheslea Green, 2013) and author of the book "The Citizen's Guide to State-By-State Marijuana Laws" (Whitman Press, 2015).

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