New research from Washington state shows that legal marijuana appears to debunk the “gateway drug” theory.

New data shows some of the benefits of legal marijuana. Published in the Journal of Adolescent Health, the data links legal cannabis sales with a decrease in the use of alcohol, cigarettes, and pain medications in young adults.

The study was conducted by researchers from the University of Washington, who noticed trends in substance consumption in people between the ages of 18 to 25 following the legalization of marijuana in their state.

Researchers explained that the study demonstrated a converse effect to what many predicted with the legalization of cannabis. “Contrary to concerns about spillover effects, implementation of legalized non-medical cannabis coincided with decreases in alcohol and cigarette use and pain reliever misuse,” they wrote.

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While they suggest that the link between legal marijuana and the weakening of the consumption habits of other drugs should be looked into, their results “may suggest increased importance of cannabis-specific prevention and treatment efforts.”

In any case, the study proves one of the main criticisms against legal cannabis: the “gateway drug” argument, which claims that having access to marijuana facilitates the consumption of other drugs.

“Real-world data from legalization states disputes longstanding claims that cannabis is some sort of ‘gateway’ substance,” said NORML’s Deputy Director Paul Armentano. “In fact, in many instances, cannabis regulation is associated with the decreased use of other substances, including many prescription medications.”

Teen and young adult use is one of the main concerns of legal marijuana, with responsible parties concerned about the drug’s effects on young brains. The evidence that exists is conflicting and difficult to parse, made more complicated due to marijuana’s illegality on a federal level.

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“A lot of the literature on cannabis legalization is difficult to compare due to differences in state policies, the states included in each paper’s analysis, the time periods that researchers are examining, the way use is defined, and other issues,” said Nicolas Schlienz, Ph.D., research director at cannabis education platform Realm of Caring.

Studies on marijuana show how little we know about the drug and its effects on the population. In order to get an accurate picture of its effects on people and our communities, more studies are needed along with more freedom for researchers who are interested in asking the necessary questions.