A new research suggests that access to medical marijuana may have trimmed down the use of opioids.

Researchers from Columbia University's Mailman School of Public Health have analyzed traffic fatality data from 1999 to 2013.

It has been discovered that the states, which approved laws for cannabis consumption, saw a decline in fatal crash cases involving drivers who tested positive for prescription painkillers.

The study, which was published in the American Journal of Public Health, is among the first to investigate the link between state laws regarding medical weed and the use of opioid.

Authors have pointed out that reduction in opioid positivity among 21- to 40-year old fatally injured drivers is associated with medical marijuana laws. The mean annual opioid overdose mortality rate has dropped to 24.8 percent in places allowing cannabis consumption.

There is a boom in painkiller abuse across the United States. Since 1999, opioid prescriptions and sales have quadrupled. In 2014, more than 14,000 people have died from overdoses of prescribed opiates. The Columbia research is part of growing evidence that weed can be an effective and alternative relief for pain and its related issues.

In July, documentations have revealed that states with medical marijuana saw a drop in prescription drugs and saved an estimated $165.2 million in Medicare expenses.

Last March, federal health officials released new regulations to curb the painkiller abuse by urging doctors to avoid prescribing highly-addictive drugs like OxyContin and Vicodin when treating patients with chronic pain.

However, the methodology used by the authors has been scrutinized by other experts in the field. The fact that the study did not use medical marijuana in place of opioids is an added disadvantage.

According to Jason Hockenberry, Director of Graduate Studies with the Department of Health Policy and Management at Emory University, any benefit of medical weed need to be balanced against the negative effects of marijuana. He added that, aside from cannabis abuse, his own work saw an increasing dependency in states with medical weed laws.