CBS Local — The ability to use marijuana legally in Colorado has reportedly resulted in a positive side-effect: a decrease in the number of fatal opioid overdoses in the state.

According to a new study by the American Journal of Public Health, the number of overdose deaths have fallen by more than six percent since the state legalized recreational pot in 2014.

“Colorado’s legalization of recreational cannabis sales and use resulted in a 0.7 deaths per month reduction in opioid-related deaths,” researchers wrote.

While fatal overdoses have dropped in Colorado, local officials are skeptical of the connection to legal marijuana. “It just hasn’t been in place long enough,” Dr. Larry Wolk said, via The Denver Post. “Anything that does get published at this point should be considered preliminary data,” the director of the Colorado Department of Public Health added.

The Centennial state’s drug prevention community is also denouncing the study as a simple answer to a complicated topic. “The whole thing is so convoluted, with so many different things going on in the marketplace, it’s virtually impossible to assign cause and effect or credit and blame to any one thing,” Consortium for Prescription Drug Abuse Prevention coordinator Robert Valuck said.

The study is reportedly the first to single out recreational marijuana as a cause for a drop in opioid-related deaths. A number of studies have drawn a link to the legal use of medical marijuana and the reduction in overdoses from using painkillers across the country.