BALTIMORE — Vaping may be viewed as a “safer” way to consume marijuana, but a recent study shows it may lead to more unpleasant mental experiences among those who don’t use cannabis often.
Researchers at Johns Hopkins Medicine found in a small study of infrequent cannabis users that vaping causes stronger effects than smoking it even when the dosages were the same. In particular, participants were more prone to short-term anxiety, paranoia, memory loss, and distraction.
Vaporizers work by heating the cannabis plant to a high temperature, causing the psychoactive effects of the drug to be vaporized and inhaled by the user. Unlike cannabis smoke, the vapor doesn’t produce harmful chemicals from burning material, such as tar and other carcinogens.
According to the study, however, vaping also delivers higher amounts of THC, the most active mind-altering compound in cannabis.
“There’s a definite difference in the amount of drug making it into the blood when using a vaporizer versus smoking the drug, so considerations need to be made when dosing to ensure people are using cannabis safely,” says study co-authors Tory Spindle, a postdoctoral fellow researcher in the behavioral pharmacology research unit at Johns Hopkins Bayview, in a release.
The researchers tested for cannabis effects in 17 adults who hadn’t used cannabis in at least a month, and on average hadn’t used in a year. Participants smoked or vaped cannabis with various dosages of THC (0, 10 or 25 milligrams) in a controlled lab setting at Hopkins once a week over six weeks. Researchers say 25mg tends to be a lower dosage than what’s typically found in pre-rolled joints at dispensaries.
Researchers recorded the severity of the effects of both smoking and vaping were among participants using the Drug Effect Questionnaire each hour for eight hours afterwards. The assessment measures strength of effects on a scale of 0-100. Participants reported an average of 77.5 on the strength of the drug’s effect when vaping the 25mg dosage, compared to 66.4 when smoking the same dose. Anxiety and paranoia tended to be about 7% stronger from vaping, and participants reported significantly more instances of dry mouth and dry eyes than compared to when they smoked.
A computerized task that measured attention by tracking an image and numbers on a computer screen found that while performance time fell by 170% after smoking 25mg of THC, participants were 500% worse when the same amount was vaped.
“Our participants had substantially higher impairment on the tasks when vaping versus smoking the same dose, which in the real world translates to more functional impairment when driving or performing everyday tasks,” says Spindle.
Among the less frequent side effects, two participants vomited after vaping 25mg of THC, and another reported hallucinations. One person vomited after smoking a 25mg dosage.
“In light of increased legalization of cannabis, we designed our study to be more representative of the general population’s exposure to cannabis, namely someone who has never smoked it and wants to try it for medical or recreational purposes, or someone who does not use it regularly enough to understand or predict its effects,” adds Dr. Ryan Vandrey, associate professor of psychiatry and behavioral sciences at Hopkins. “What our study suggests is that some people who use cannabis infrequently need to be careful about how much cannabis they use with a vaporizer, and they should not drive, even within several hours after use. It could be dangerous for themselves and others, and on top of that, they may experience negative effects such as anxiety, nausea, vomiting and even hallucinations.”
The researchers hope that their work will lead to more consideration of dosage and the perception that vaping cannabis is safer than smoking it.
The study was published in JAMA Network Open.