Vaporized Cannabis Produces Stronger High Than Smoking for Infrequent Users
Vaping cannabis can produce stronger effects — for better or for worse — than smoking an equivalent amount, according to a recent study published in the American Medical Association journal, JAMA Network Open. The study, performed by researchers at Johns Hopkins Medicine, is the first time that significant subjective differences have been recorded between the two consumption methods.
The growing popularity of vaporizing cannabis
For decades, smoking cannabis flower was the most popular way to use the drug. With cannabis remaining widely prohibited, there was little incentive to develop anything more novel than perhaps the very European approach of mixing cannabis flower with tobacco and smoking that mixture. The “hippie” counterculture of the 1960s brought with it the invention of glassware water pipes which claimed to purify the cannabis smoke using water filtration, but the continued prohibition of cannabis products never allowed new consumption methods to break into the mainstream.
With many states and countries now making the decision to end cannabis prohibition, we are beginning to see more product development and invention which focusses on cannabis consumption methods. One of the most popular and predominant new methods is the cannabis vaporizer, or more simply, the vape.
Instead of directly burning cannabis material, as is done in smoking, cannabis vapes heat up cannabis flower or concentrate to temperatures where the THC (tetrahydrocannabinol, the primary intoxicant in cannabis) begins to aerosolize into a vapor that can be inhaled. Vaping is often considered a more discreet method of consuming cannabis, with the characteristic smell of the drug being much harder to detect during vaping, and the vapes themselves being easier to transport and use than cannabis joints or cigarettes. Many also believe that vaping is a safer alternative to smoking cannabis flower as the absence of burning material means there will not be significant levels of dangerous combustion products being inhaled alongside the THC when vaping.
As a result of this sort of ease, the popularity of vaping has grown sharply; product data from the Californian cannabis delivery service, Eaze, showed a 400% annual increase in the delivery of cannabis vape cartridges from 2015 to 2016. With vaping becoming more mainstream, it is important to study this to identify any substantial risks or differences to other methods.
Methodology used in the study
This study comprised 17 participants, all of which were infrequent cannabis users. Infrequent use was defined as no use within the past 30 days and this was confirmed using urine toxicology tests.
It was felt that previous comparison studies were limited by the study of only single THC doses, small sample sizes, and the practice of requiring participants to use specific breathing patterns. To correct for this in this study, all 17 participants took part in six distinct study sessions separated by at least one week and were allowed to consume the cannabis used in a natural breathing pattern.
Each participant smoked or vaped cannabis containing either 0, 10 or 25 milligrams of THC. The study was conducted under a double-blind, so both participants and the study staff administering the dosages were not told which dose was administered in any given session. Vaping was done by inhaling completely vaporized cannabis product from opaque balloons, to rule out any visual difference between cannabis vapor of different strengths. In the smoking sessions, a metal cover was used to obscure the drug material from the handheld pipes used. Dosages were altered by mixing a placebo and a high-THC cannabis strain obtained from the National Institute on Drug Abuse Drug Supply Program. This created blends of different THC concentration but of similar weight, to avoid weight being a possible identifying factor in the double-blind. Non-blinded research staff ensured that the complete dose was consumed in each instance.
Following consumption, participants were asked to assess the subjective drug effects they were experiencing — including but not limited to sleepiness, dry mouth, and generally pleasant drug effects — using a Drug Effect Questionnaire (DEQ) previously described in a publication in the Journal of Analytical Toxicology. Physical effects were studied using blood samples as well as by recording heart rate, blood pressure, and performance in cognitive and psychomotor performance tasks. All effects were analyzed at multiple time-steps (including a baseline before any cannabis was consumed) and results were compared using statistical analysis to identify any significant variation between the consumption methods.
A stronger high, with stronger side effects
Results from the DEQ revealed that those who vaped the cannabis generally reported feeling more intoxicated than those who had smoked. This was particularly evident at the 25 milligram dosage, where the average DEQ score was 77.5 out of 100 when vaping, but only 66.4 when the same dose was administered through smoking. Feelings of anxiety and paranoia were reportedly on average 7 percent higher when the 25 milligram dose was vaped rather than smoked. At both the 10 mg and 25 mg dosages, reports of dry mouth and dry eyes were also significantly more frequent when participants had vaped the dosage.
Reaction times were on average 120 milliseconds slower when using any active dosage level, either smoked or vaped, compared to the placebo. However, those who had vaped performed significantly worse on the Divided Attention Task than those who had smoked the same dosage. At the 10 milligram dosage performance was on average 350 percent worse when vaping, and at the 25 milligram dose this grew to a performance drop of 500 percent compared to those who had smoked an equivalent amount. Blood tests revealed that the levels of THC in the blood were also higher in those who had 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,” explained first author Tory Spindle, Ph.D., to the Newsroom at Johns Hopkins Medicine. “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.”
By designing the study to focus on infrequent users, the researchers aimed to model what the average first-time recreational user might experience when first using cannabis. From the differences in intoxication between the two methods observed here, it is clear that vaping can bring on more pronounced drug effects and more obvious impairment. Studies such as this can help novice cannabis users to make informed decisions concerning what might be a safe and controlled initial dosing plan for their individual needs. Future studies using populations with a more varied cannabis use history, as well as the study of different vaporizers (e.g. vaporizers that use cannabis concentrate rather than flower) and wider array of cannabis potencies are needed. These findings could also prove helpful to both individuals and to the medical professionals who are responsible for creating medicinal cannabis treatment plans.
