Study Looks At The Relationship Between THC Levels In Flowers And Concentrates And Impairment

Cannabis flowers have long-dominated users’ stash boxes as the traditional and most common form of consumed cannabis, though concentrate-based products in various forms have become very popular in recent years with the spread of legalization.

Once a more-rare form of cannabis, concentrates are now standard fare at most medical and adult-use dispensaries across the country.

Through selective breeding, savvy growers have managed to create cannabis strains that have delta-9 tetrahydrocannabinol (THC) levels in the 30-40 percent range, but with the introduction of distillate, a highly-potent cannabis oil, THC levels in some concentrate products are above 90 percent.

But while cannabis concentrates have a higher percentage of THC, increased potency does not necessarily translate to increased impairment of the user.

A new study from researchers at the University of Colorado, Boulder (CU Boulder) published online in the JAMA Psychiatry journal explores how the THC content in legal market cannabis flowers and concentrates relates to intoxication and neurobehavioral impairment.

Conducted in a university and community setting, the study group consisted of 55 cannabis flower users who were randomly assigned to use dispensary-bought products containing 16 to 24 percent THC, and 66 concentrate users who were randomly instructed to use products with 70 to 90 percent THC.

Of the 133 participants enrolled in the study and assessed, 121 complied with the study’s use instructions and had complete data across primary outcomes.

Researchers could not legally bring cannabis to the CU Boulder campus for the study, so the team utilized two white Dodge Sprinter vans as mobile laboratories, dubbed the cannavans, which they drove to study subject residences.

Researchers drew blood and measured subjects’ mood and intoxication levels on test days, assessing their cognitive function and balance before, during, and one hour after using cannabis.

According to study results, short-term use of cannabis products did not alter most neurobehavioral measures, though delayed verbal memory and balance function were impaired after use.

“Surprisingly, we found that potency did not track with intoxication levels,” says lead author Cinnamon Bidwell. “While we saw striking differences in blood levels between the two groups, they were similarly impaired.”

Researchers speculate that cannabinoid receptors may become saturated with THC at higher levels, diminishing the effects of consuming additional THC.

Professor of Psychology and Neuroscience at CU Boulder and study co-author Kent Hutchison says that the people in the high concentration group were much less compromised than anticipated and that if participants had consumed the same concentration of alcohol, the results would have been a different story.

The authors of the study caution that their research examined experienced users who have learned to appropriately meter their dosage, based on the desired effect, and does not apply to inexperienced users.

The researchers urged newer cannabis users to exercise caution with concentrates.