The number of injured veterans using medical marijuana has skyrocketed, according to Veterans Affairs Canada, while opioid use has decreased.

A cocktail of pills and prescription drugs was once the only option for struggling veterans dealing with painful, life-changing injuries.

Retired Army Maj. Mark Campbell lost both legs after an explosion during his last tour in Afghanistan. He had been given opioids and other prescription drugs to reduce the pain.

But it was only when his doctor prescribed him medical cannabis that Campbell said he felt real relief. He now calls weed “magic.”

“[It] allowed me to reduce my own opioid [use and] my own consumption of pills by about 50 per cent,” he told CTV News. “Veterans wouldn't turn to marijuana if it didn't work for them. That's the bottom line. No one is looking to get high all the time.”

Campbell is part of a growing number of Canada’s veterans who are turning to cannabis for help.

New data from Veterans Affairs Canada found that around 10,000 vets used medical marijuana last year -- compared to only 1,700 vets in 2015. And that surge is costing the department $65 million in prescription payouts.

Although there is no proven direct link, the increase in medical cannabis use has coincided with a decrease in reimbursements for traditional painkillers.

In the last five years, payouts for veterans’ opioid prescriptions for fentanyl have dropped 85 per cent, while payouts for oxycodone have dropped by 75 per cent.

Riad Byne, CEO and co-founder of the Spartan Wellness veteran wellness centres, has seen this shift happen firsthand.

“Going off opioids numbs you and you become closed and depressed,” he said.

Zachary Walsh, psychology professor at the University of British Columbia, said the potential for medical marijuana is encouraging.

“One of the exciting potentials with cannabis is that it can treat several of those symptoms at once,” he told CTV News. “Many veterans report it helps with their pain, their sleeping and their anxiety.”

But as pot use rises, researchers are calling for more studies to determine the full extent of the benefits and risks connected to cannabis use, particularly when it relates to pain relief.

However, despite Veterans Affairs Canada filling out their cannabis prescriptions, veteran advocates said the department is still failing them.

Advocates told CTV News that the department needs to do a better job clearing backlogs for disability benefits and hiring more service providers.