A survey by Yale University revealed teens have discovered a way to vaporize marijuana using e-cigarette devices. Some experts have serious concerns.

Teenagers have discovered a clever but potentially dangerous new use for e-cigarette devices — vaporizing marijuana.

A Yale University study, published this week in the journal Pediatrics, found that of 3,847 Connecticut high school students surveyed, 28 percent reported using e-cigarettes. Of those, 18 percent have used the devices to vaporize concentrated liquid marijuana or hash oil.

Users said they prefer vaping because it offers secrecy and cannot easily be detected.

But researchers said the practice can produce a higher-potency high that can be injurious to teens and young adults during crucial brain-development years.

Meghan E. Morean, Ph.D., lead author of the study and now assistant professor of psychology at Oberlin College, told Healthline that e-cigarette use among American teenagers has been on the rise.

“This is a relatively novel way of using marijuana and kids are using it at a fairly high rate,” she said.

Morean conducted the research while in the lab of the study’s senior author, Suchitra Krishnan-Sarin, Ph.D., professor of psychiatry at Yale.

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When an e-cigarette user inhales, the batteries that power the e-cigarette device activate a heating element. This vaporizes a liquid-nicotine solution stored in small tubes.

Some young e-cigarette users are taking advantage of this process to vaporize liquid marijuana or hash oil, which contain concentrated THC (tetrahydrocannabinol), the principal psychoactive ingredient in cannabis.

Morean said several articles in the media prompted her to do the survey.

“We also got wind of this from adolescent participants we have worked with in other unrelated studies,” she said.

When Morean couldn’t find any published studies on that specific topic, the Yale lab went ahead with its own.

“We were curious and wanted to know to what extent high school students in Connecticut were using e-cigarettes to vaporize cannabis,” she said.

Vaporized marijuana does not have as strong a smell as smoked pot, Morean said.

“Plus the similarity in appearance of hash oil and nicotine solutions make this a really inconspicuous way of using marijuana,” she said.

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Both Morean and Krishnan-Sarin stressed their survey does not evaluate whether the availability of e-cigarettes leads to more marijuana use by teens.

They noted, however, that vaping concentrated liquid forms of marijuana can be more potent than smoking dried marijuana leaves.

Other researchers have also discovered troubling outcomes from vaping pot.

Susan Weiss, Ph.D., is director of the Office of the Division of Extramural Research at the National Institute on Drug Abuse of the National Institutes of Health.

“If the concentrated form that is vaped has much higher levels of THC — which has been suggested anecdotally — then the person may be exposing their brain to higher doses of THC,” Weiss said in an interview with Healthline. “That makes the effects less predictable. For example, some people find that high doses make them anxious and paranoid.”

Weiss noted the physiochemical differences between smoking and vaping marijuana.

“Smoking the plant causes the release of combustible products that can be toxic to the lungs, similar to smoking cigarettes,” she said. “With vaping, the temperature does not get as high, so it is thought to be safer. But there are many unknowns, particularly since the products are unregulated and may contain other toxins, such as lead.”

Using marijuana poses additional dangers for teens.

“We are still trying to understand how marijuana affects the adolescent brain,” Weiss said. “We know the brain continues to develop into young adulthood, to about age 25. A growing body of evidence suggests that early and frequent marijuana use may disrupt teen brain development in some users.”

Weiss said there are many unanswered questions about causality. These include whether the brain of a regular marijuana user differs before use of the drug, and how the use of other substances, such as alcohol, interacts with marijuana exposure.

“When you consider the role of the endocannabinoid system — where marijuana acts — in brain development, and many other functions such as memory — along with some of the disturbing outcomes associated with frequent marijuana use, such as higher rates of school dropout and lower income — this may be a risk not worth taking with one’s developing brain,” she said.

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A Virginia-based advocacy group, Parents Opposed to Pot (POP), strongly agrees.

Roger Morgan, a director of POP, which works to combat state-ballot initiatives to legalize marijuana, told Healthline he has serious concerns.

“Anyone under 25 should be worried about marijuana because it causes brain damage,” he said. “The younger one [is when they use], and the more one uses, the greater the damage. Marijuana doesn’t kill by overdose, like cocaine, meth, or heroin, but by the incredible rise in potency. It’s leading to heinous acts of murder, suicides, traffic deaths, and crime.”

Scientists have previously examined how smoking dried marijuana leaves affects the teenage brain.

One long-range project investigated persistent marijuana use before age 18 (and up to age 38) by 1,037 New Zealanders. Researchers said they found lasting harm to users’ intelligence, attention, and memory, including an average decline in IQ of eight points.

That study was led by Madeline Meier, Ph.D., then a postdoctoral researcher at Duke University, now assistant professor of psychology at Arizona State University. The results were published in August 2012 in the journal Proceedings of the National Academy of Sciences of the United States of America.

Meier, in a video interview transcript posted on the website of the National Institute on Drug Abuse, said regular teen cannabis users who stopped using the substance by adulthood still showed IQ decline.

“So, quitting as an adult didn’t result in recovery of IQ function,” she said.

“We don’t know when the damage is done, but we do think the damage is lasting. We found declines across measures of mental functions, not just IQ,” she added. “We looked at memory, executive functioning, which is the ability to multitask and plan ahead, processing speed, and reaction time.”

“We also looked at whether informants noticed cognitive problems among persistent cannabis users,” she continued. “We didn’t just look at standardized tests. We looked at how people were functioning in everyday lives, and we found that informants noticed more cognitive problems [and] attention and memory problems, among persistent cannabis users.”

Meier said the crucial variable is the age at which marijuana use begins.

“Subjects who didn’t take up pot until they were adults with fully-formed brains did not show similar mental declines,” she said. “Before age 18, however, the brain is still being organized and remodeled to become more efficient and may be more vulnerable to damage from drugs. Marijuana is not harmless, particularly for adolescents.”