“(I was) coming out of an intense panic situation, thinking I was in, literally, hand-to-hand combat and not knowing whether I was dreaming or what was reality,” recalled Lopez, now 34 and out of the military.

Recognizing he was experiencing symptoms of PTSD, Lopez dismissed taking strong synthetic drugs he says are often prescribed by the Department of Veterans Affairs. Instead, he turned to what he had dabbled with for much of his life: psychedelic mushrooms.

Lopez is among a group of veterans, natural medicine proponents, mental health advocates and entrepreneurs backing a ballot initiative in Colorado this November that would decriminalize so-called “magic mushrooms” for those 21 and older and create state-regulated “healing centers” where participants can experience the drug under the supervision of a licensed “facilitator.” Military veterans like Lopez have been at the forefront nationally of trying to persuade lawmakers to study psychedelic mushrooms for therapeutic use.

If the initiative passes, Colorado would join Oregon in establishing a regulated system for substances like psilocybin and psilocin, the hallucinogenic chemicals found in some mushrooms. After June 1, 2026, Colorado would allow an advisory board to add other plant-based psychedelic drugs to the program, including dimethyltryptamine, commonly known as DMT, ibogaine and mescaline not derived from peyote, a type of cactus that some conservation groups are trying to protect.

The ballot initiative comes a decade after Colorado voted to legalize recreational marijuana, which led to a multi-billion-dollar industry with hundreds of dispensaries popping up across the state.

Proponents argue that jailing people for the non-violent offense of using naturally occurring substances costs taxpayers money. They also say the state’s current approach to mental health has failed and that naturally occurring psychedelics, which have been used for hundreds of years, can treat depression, anxiety, addiction, post-traumatic stress disorder and other conditions.

“When I’m on psychedelics, for example, like mushrooms or psilocybin, it opens my eyes to the beauty of the world, the love that I have for the world. … All of that anger, or being upset or frustrated … it dissolves. It melts away,” said Lopez, who also took part in the successful campaign to legalize recreational marijuana in Colorado.

But critics of the latest ballot initiative note that the Food and Drug Administration has not approved the psychedelics as medicine. They also argue that allowing “healing centers” to operate, as well as allowing private personal use of the drugs, would jeopardize public safety and send the wrong message to kids and adults alike that the substances are healthy.

“I am going to take medical advice from doctors and scientists over entrepreneurs any day of the week,” said Luke Niforatos, the head of the ballot committee, Protect Colorado’s Kids, which opposes drug legalization and decriminalization efforts. “We should listen to the American Psychiatric Association. We should listen to the FDA. We should listen to our doctors. We should not be listening to people with a profit incentive.”

Niforatos said the same deep-pocketed players who have pushed for legalizing recreational marijuana in various states are behind the latest initiative and are using a “drug legalization playbook” to create a commercial market that could eventually lead to recreational dispensaries for dangerous and federally illegal substances.

Natural Medicine Colorado, the group behind the initiative, has raised about $5.4 million. About three-quarters of that — $4.2 million — has come from New Approach PAC, a national drug policy group that also is financing marijuana measures in some other states.

“They started with medical marijuana and then went to recreational marijuana. Now they’re starting with medical psychedelics. We can only assume that they’ll go to recreational psychedelics from here,” said Niforatos, whose group has raised about $50,000. He warned that the use of the drugs could cause prolonged psychosis, persistent hallucinogenic disorders and lead to impaired driving.

Mason Tvert, who spearheaded the campaign to legalize recreational marijuana in Colorado in 2012, said the push to decriminalize psychedelic mushrooms and other natural substances differs from the recreational marijuana campaign because, this time, voters are not being asked to allow dispensaries.

“We’re voting on whether to allow (psilocybin) in very limited environments involving a great deal of control and safety and professionals,” said Tvert, a partner a VS Strategies, a Denver-based drug policy and public affairs consulting firm.

The psychedelics that would be decriminalized if the initiative passes are listed as schedule 1 controlled substances under state and federal law and are defined as drugs with no currently accepted medical use and a high potential for abuse.

Even so, the FDA has designated psilocybin a “breakthrough therapy” to treat major depressive disorder. The designation can expedite research, development and review of a drug if it might offer substantial improvements over existing treatments.

A preliminary study published Wednesday in the New England Journal of Medicine also found that psilocybin may ease depression in some hard-to-treat patients. The modest effects waned over time, but they helped people who previously had gotten little relief from standard antidepressants.

Colorado’s ballot initiative would allow those 21 and older to use, grow, possess and share the psychedelic substances but not sell them for personal use. It also would allow people who have been convicted of offenses involving the substances to have their criminal records sealed.

Those who want to use mushrooms would not need approval from a doctor. In addition to being able to grow and use their own mushrooms, those who want to try the therapy could do so through the newly formed “healing centers,” which would be allowed to supply clients with mushrooms but not sell them. Instead, clients would pay for the services of the “facilitator” at the center.

In 2020, Oregon became the first state in the nation to legalize the therapeutic, supervised use of psilocybin after 56% of voters approved Ballot Measure 109. But unlike Colorado, the state allows counties to opt out of the program if their constituents vote to do so.

In Colorado, counties and municipalities would be able to regulate “healing centers” but not ban them.

Oregon’s initiative is expected to take effect at the beginning of next year, and if passed, Colorado would start outlining regulations no later than the beginning of 2024.

Washington, D.C., and Denver have already partially decriminalized psychedelic mushrooms by requiring law enforcement officers to treat them as their lowest priority. Outside of certain scientific research contexts, the substances would remain illegal under federal law even if Colorado’s initiative passes.