For the first time ever, heroin is more likely to kill us than guns. According to the Centers for Disease Control, heroin deaths surpassed gun deaths in 2015, a harsh reminder of the growing public health crisis that is opioid addiction. Opioid use grew quickly in the U.S. outpacing doctors' and lawmakers' abilities to understand the problem and react appropriately. Now we're playing a very deadly game of catch up, but some studies show there could be one unexpected answer in the search to easing heroin overdose deaths.

Colleen Barry, a professor at the Johns Hopkins Bloomberg School of Public Health and co-director of the Johns Hopkins Center for Mental Health and Addiction Policy Research, wrote in the New York Times that her and her team found opioid overdose deaths decreased significantly — by as much as 25% - in states that made medical marijuana legal. According to her study, after the passage of legal medical marijuana, states saw a reduction in prescription opioid overdose deaths in the first year, and that only grew in following years. Colleen's isn't the only study that makes the same point, though. Stat News points to two other studies that also show a drop in overdose deaths after medical marijuana is made legal.

According to one of the studies, the reason for that could be that doctors write fewer opioid prescriptions once marijuana is available as a pain reliever. Opioids include drugs like heroin, but are also strong pain relievers subscribed by doctors to tons of patients - you probably got some when you got your wisdom teeth out. The issue is opioids are highly addictive, particularly if you're in pain and they are the only thing that helps. Eventually, your body becomes hooked, and once your prescription runs out and you can no longer afford to buy opioid pills illegally, many people switch to heroin because it's cheaper and easier to find. According to Stat, 3 out of every 5 opioid overdoses occurs in someone with a legitimate prescription, so you can see how thin the line between prescription and substance use disorder becomes. If doctors are able to prescribe marijuana instead of opioids, that means one less person likely to get hooked.

Dr. Constance Scharff, PhD, the research director of Cliffside Malibu treatment center in Malibu, California, said for those reasons, marijuana could be life saving.

"In states where medical marijuana is legal, research shows that opioid overdose rates have decreased by 25%. With an estimated 50,000 deaths expected from opioid overdose in the US in 2016, this represents a significant lifesaving impact. Why do we see these results? Marijuana has painkilling properties," Dr. Constance said. "When given a choice between legal marijuana and opioid painkillers, a significant number of people with pain conditions seem to choose marijuana, which is far less lethal than opioids."

According to procon.org, 28 states and Washington D.C. have legal medical marijuana laws on the books. Some of those states just joined the ranks, so it will be interesting to see whether the trend in lowering opioid overdose deaths continues.

"We should encourage the legalization of medical marijuana. Individuals have a right to choose what they believe is the best medical treatment possible," Dr. Constance said. "For pain, particularly chronic pain conditions, many prefer marijuana over opioids. Marijuana provides pain relief and though it is addictive, it does not pose the overdose threat that opioids do."

Related: Drug Use Has Actually DECLINED Since More States Legalized Marijuana