OKLAHOMA CITY - A Texas doctor has crossed state lines to speak out about the dangers of marijuana. His visit comes ahead of this summer's vote to legalize medical marijuana in Oklahoma.

Chronic pain patients are hoping it passes, but Dr. Harold Urschel says there are serious concerns. He spoke to the Oklahoma Medical Board Wednesday about the effects of marijuana on the brain. He says he sees the impact it can have, through his work as the Chief Medical Strategist at Dallas’s Enterhealth Addiction Treatment facility.

Urschel says do not believe the myth that says marijuana is not addictive. He says the recent dramatic increase in levels of the drug's psychoactive compound THC is not helping users.

“The more concentrated it is, the more addicting it is,” he says, “because the better high you get and the more destructive it is to the brain and the longer it lasts in your brain, corroding your brain the whole time it’s in there.”

Supporters of State Question 788 argue medical marijuana typically has a low THC percentage, however, in favor of a higher CBD level, which patients laud for its therapeutic properties.

Yes on 788 campaign organizer William Jones says, “The main compound in marijuana is non-addictive and non-toxic to humans. It’s the main compound in medical marijuana.”

Many Oklahomans are already turning to legalized CBD products for help with chronic conditions, but they are banking on medical marijuana to give them further relief.

Jessica Hawkins, who suffers from autoimmune disorders fibromyalgia and Lupus, says, “Sooner born, Sooner bred. When I die I’ll be Sooner dead, but I might not be because I don’t want to stay here if I don’t have access.”

Dana McMurchy says CBD oil almost immediately helped end her decades-long dependency on alcohol.

“To be able to have my anxiety go down and my alcohol stop, that’s a healthy thing for me,” she says.

But Urschel believes any form of legal marijuana is a smoke screen that opens the gateway to recreational use.

“There’s so many better, safer medications out there to treat the things that people are using marijuana for,” he says, “the people that want to use marijuana, they’re just making up an excuse.”

Urschel also tells News 9 that marijuana keeps the brain from properly processing oxygen, and from properly developing in adolescents.

He says that if the measure does pass, there should be stricter regulations put in place here than in other states.

“We could know who’s getting the marijuana, what is it for, what’s the dose the they’re getting, how long they’re using it,” he suggests, “all of those things that are not being tracked in any way, shape, form or fashion.”

Ideally, though, Urschel wants patients who are battling pain and addiction to seek out mental health help or speak to a religious leader in the community to uncover the root cause of their dependency.

He says, “The fact is, opiates are really bad for you. Marijuana is really bad for you. We should be having neither.”

You can cast your vote on the issue June 26.

To learn more about Urschel’s work, click here.

To learn more about the Yes on 788 campaign, click here.