Trevor Hughes

USA TODAY

DENVER — A casual marijuana smoker, Kyle Naylor figured he'd give edible marijuana products a try to see if they'd curb his anxiety and insomnia. It didn't go well.

Eighty minutes into his experiment, Naylor got intensely sick and lost control of his body. By 90 minutes, he was hyperventilating, freaking out and heading to the emergency room.

"For me, the effect from smoking marijuana was completely different than ingesting it," says Naylor, 30.

On Jan. 1, Colorado became the first state to legalize recreational use of marijuana — Washington state expects to begin legal retail sales this summer — and commercially made edible products have become a popular alternative to smoking pot.

Though brownies laced with illegal marijuana have quietly made the rounds at parties around the USA for decades, adults now can walk into state-licensed stores here and buy professionally manufactured edibles, from candy to soda and granola.

But this is not just a story about happy highs. Two deaths connected with edible marijuana products have Colorado lawmakers scrambling to toughen regulations and experts warning of bizarre behavior as consumers eat powerful pot-infused foods.

Experts say the amount of marijuana in edibles can vary widely, and in some cases, the levels are so high people report extreme paranoia and anxiety bordering on psychotic behavior.

"You can feel like you're dying," says Genifer Murray of CannLabs, a Colorado-approved marijuana potency testing lab. Murray says inexperienced users easily can overdose on marijuana edibles because the effects take longer to kick in than smoking.

The concerns follow two nationally prominent incidents. In the first, a college student from Wyoming jumped to his death March 11 from a Denver hotel balcony after eating a marijuana cookie. Witnesses told police that Levi Thamba Pongi, 19, was rambling incoherently after eating a large serving of the doped cookie. The Denver coroner ruled that "marijuana intoxication" was a significant factor in his death.

And Richard Kirk of Denver faces first-degree murder charges stemming from the fatal shooting of his wife inside their home in April. Kirk's wife called 911 to report he was hallucinating and rambling after eating marijuana candy and taking prescription medication. Kristine Kirk died while on the phone with a police dispatcher.

"On the recorded call, Mrs. Kirk can be heard telling Richard to stay down and yelling for her kids to go downstairs," according to a search warrant affidavit. "At one point, Mrs. Kirk tells the 911 operator 'please hurry' because he was scaring the kids and he was 'totally hallucinating.' "

Edibles give users a different kind of high than the one they get from smoking marijuana, largely because the pot is absorbed through the stomach instead of the lungs. The effects are slower to arrive, generally last longer and can be more intense because people unwittingly eat more than they intend to. On the other hand, people who smoke pot get high quickly, allowing them to better regulate how stoned they're getting.

"When you're smoking, you reach a certain level of highness ... and forget to keep smoking," says Denver forensic psychologist Max Wachtel, who counsels youth offenders. "It's in our nature to accidentally overuse edibles."

Naylor says that's what happened to him: He ate the recommended dose of ¼ of the cookie and waited an hour. When nothing happened, he ate more. "I didn't realize it would be such an intense and different high after that long," he says.

Under regulations that took effect last week, edible marijuana products cannot contain more than 100 mg of THC, the compound in marijuana that gets users high. But there's no standard for the size of those products. That means one candy bar can contain the same amount of THC as an entire bag of cookies.

The regulations apply only to marijuana for recreational use; medical marijuana products can be much stronger but are available for legal purchase only with a doctor's recommendation.

Colorado lawmakers agreed this week to spend $10 million to study the effects of marijuana use and to require better labeling of edibles, while barring them from being made into products "primarily marketed to children."

Lawmakers also approved a measure that would lower the amount of marijuana-infused oil or butter that can be sold to consumers. Infused oils and butters contain concentrated marijuana at levels far higher than contained in the plant itself.

State regulators are considering whether to mandate portion sizes, which would help standardize the amount of marijuana in a candy bar or a soda.

Legalization opponents such as state Rep. Frank McNulty say the brightly packaged edibles appeal to kids who might not stop to read the tiny print warning that a Tootsie Roll-size candy contains the equivalent of multiple joints. Opponents also worry about the easy availability of edibles. On April 22, a school in northern Colorado suspended several students who brought both marijuana and pot edibles into the building, which they said they stole from their grandparents.

"They need to stop lacing kids' snacks with THC … and standardize these servings," says McNulty, a Republican who represents the Denver suburb of Highlands Ranch. McNulty sponsored two bills that would toughen marijuana regulations this legislative session. "Whatever is in that brownie, you're on it for the entire ride. There's no ability to self-regulate with edibles."

Wachtel, the psychiatrist, says the difference between smoking a joint and consuming an edible is much like that between drinking hard liquor and beer. You can slam five shots before feeling the effects but can tell you're getting drunk after drinking five beers.

"You're getting a ton more THC" in edibles, Wachtel says. "There's a real potential for danger."

Murray of CannLabs says Nayor's experience is fairly typical for first-time users of edible products. CannLabs is one of a handful of labs certified by Colorado to test marijuana edibles for potency and contaminants.

She says scientific testing is an important safeguard for consumers, especially first-time users. "You need to make sure you know what's in it and how it's going to affect your body," Murray says.

Because Colorado is the first state to legalize recreational marijuana, regulators have no best-practice rules to borrow from other states or the federal government, which considers marijuana an illegal drug, says Lewis Koski, director of Colorado's Marijuana Enforcement Division. "We were really starting from scratch," he says.

Supermarket foods and meats, along with alcohol and tobacco, are regulated at the state and federal levels. Prescription drugs must undergo extensive safety tests and regulatory scrutiny before being sold to the public, and even then only with a doctor's guidance.

Manufacturers of edible products say it's easy to eat too much, but they dismiss the idea that someone who gets high from eating pot candy would grab a gun or jump off a balcony.

"If you eat too much marijuana, you have hot flashes and cold flashes and then you get under the covers and pass out. You don't start waving a gun around," says Steve Horwitz of Denver's Ganja Gourmet. ""Any marijuana user who consumes edibles will, sooner or later, accidentally eat too much. It's very unpleasant."

Under the regulations that took effect last week, edible products will be tested for strength and how well the marijuana is dispersed within a batch of brownies or candy. Batches that contain more than 100 mg of THC per package cannot be sold to recreational users. Starting June 1, smokable marijuana will be strength-tested and the results made public.

Until then, it's buyer beware.