Alcohol sales have dropped as much as 15 percent in states with legal medical cannabis, according to a new working study from the University of Connecticut and Georgia State University.

The study added information on how cannabis availability could reduce alcohol consumption, which is more harmful to individuals and society than cannabis, experts said.

To reach this conclusion, the authors of the study examined Nielsen’s Retail Scanner database and looked at “data on purchases of alcoholic beverages in grocery, convenience, drug, or mass distribution stores in US counties for 2006-2015,” and compared alcohol sales between states that enacted medical cannabis laws and those that did not, before and after the change in laws.

“We find that marijuana and alcohol are strong substitutes” for each other, the study concludes. “Counties located in [medical cannabis] states reduced monthly alcohol sales by 15 percent” after the introduction of medical marijuana laws.

Previous studies point to this conclusion as well. A 2016 analysis of beer sales in Colorado, Washington and Oregon found retail sales “collectively underperformed” following adult use cannabis regulation.

“States legalizing medical marijuana use experience significant decrease in the aggregate sales of alcohol, beer and wine,” the study concludes. “Moreover, the effects are not short lived, with significant reductions observed up to 24 months after the passage of the law.”

Since legalization took place in western United States, the alcohol industry insiders worried legal cannabis would cut into alcohol sales, from the small-time craft beer scene to giant multinational corporations. However, a growing number of alcohol manufacturers actively started embracing the cannabis industry.

In October, Constellation Brands Inc., the U.S. distributor of Corona Beer, announced its plan to create a cannabis-infused beverage with Canopy Growth Corporation. Even smaller brewiers like California’s Lagunitas, have come up with terpene-infused beers and hop-flavored THC vape cartridges this past summer.

Compared to cannabis, alcohol is more addictive, far more likely to cause vehicle accidents, and closely linked to violent and aggressive behavior. The Centers for Disease Control and Prevention found excessive alcohol use kills nearly 90,000 people each year.