In a bit of news that will surely give anti-legalization forces cause for worry, CNN reports that states that have legalized marijuana for medical purposes are reporting much lower death tolls due to painkiller overdose.

The Journal of the American Medical Association released the supporting data behind this discovery. The study reviewed medical marijuana laws and death certificate data between 1999 and 2010. During this period only 13 states had legalized marijuana for medical purposes.

“We found there was about a 25% lower rate of prescription painkiller overdose deaths on average after implementation of a medical marijuana law,” lead study author Dr. Marcus Bachhuber said in the article.

Just in the year 2010, the number of overdose deaths was down by 1,700.

While Bachbauer recognizes the facts of the data, he is quick to point out that this is not the only factor to consider, and that medical marijuana is one choice.

“It can be challenging for people to control chronic pain, so I think the more options we have the better,” he said. “But I think it’s important, of course, to weigh the risks and benefits of medical marijuana.”

Another senior author on the JAMA study, Colleen Barry, associate professor at Johns Hopkins Bloomberg School of Public Health, calls deaths due to prescription painkiller overdose a “national public health crisis”.

“As our awareness of the addiction and overdose risks … grows, individuals with chronic pain and their medical providers may be opting to treat pain entirely or in part with medical marijuana.”

This newly-discovered benefit of legalizing medical marijuana can be added to the already-existing factors of lower traffic fatalities and reduced teen marijuana use in states that have legalized pot.