Army veteran Matthew Kahl.

Xandra McMahon/CPR News

Sales of cannabis have brought in about $725 million in tax revenue to Colorado. But who are the users who pay those taxes?” Meet My420 Bus, a marijuana-friendly yoga class, and this Army veteran with PTSD.

On his second deployment to Afghanistan, Army veteran Matthew Kahl’s vehicle crashed into a ravine, throwing him from his position in the gunner's turret. He lost parts of his jaw and teeth; he had spinal injuries, facial fractures, and a traumatic brain injury. After three months, the wounded soldier was medically evacuated but his health problems were far from over.

When Kahl returned to the U.S. he was diagnosed with post-traumatic stress syndrome and struggled with chronic pain. He says he moved to Colorado as a “medical cannabis refugee.” After he got a prescription for medicinal marijuana, he began to wean himself off the countless opioids he was using to manage his pain.

“Every single day I was taking heaping piles of pills,” he said. “It took multiple swallows and glasses of water to get them all down. And the side effects were horrific.”

The cannabis helped with Kahl’s PTSD symptoms, getting him to the point where he felt he could safely leave his house. Over the years, his symptoms have subsided allowing Kahl to wean himself off the marijuana as well. "After I came off all the pharmaceuticals I started asking myself, 'Do I really need all this cannabis all the time?'” he said. “And the answer was actually, no."