Study: Potent Cannabis Doesn’t Guarantee Greater Impairment

According to researchers at the University of Colorado Boulder, smoking high-potency cannabis concentrates boosts THC levels in the blood but doesn’t necessarily get the user higher.

The study included 121 cannabis flower users and concentrate users using products legally obtained in the state. The concentrates ranged from 70 percent to 90 percent THC, while the flower ranged from 16 percent to 24 percent THC.

Lead author Cinnamon Bidwell, an assistant professor in the Institute of Cognitive Science, said the study found that “potency did not track with intoxication levels” and while the researchers “saw striking differences in blood levels between the two groups, they were similarly impaired.”

“It raises a lot of questions about how quickly the body builds up tolerance to cannabis and whether people might be able to achieve desired results at lower doses.” – Bidwell in a statement

Study participants who used concentrates had much higher THC levels in their blood before, directly after, and one hour after use – as much as 1,016 micrograms per milliliter – whereas THC levels in the blood of flower consumers topped out at 455 micrograms per milliliter. Yet, their self-reports of intoxication, along with balance and cognitive impairment measures were “remarkably similar.”

Kent Hutchison, a professor of psychology and neuroscience at CU Boulder, said that if the researchers had given people alcohol and raised the alcohol levels in their blood to similar levels, “it would have been a different story.”

“People in the high concentration group were much less compromised than we thought they were going to be,” he added.

The researchers also found that the balance among all of the study participants was about 11 percent worse after getting stoned and their memory was compromised but those effects faded within about an hour.

The study suggests that regular cannabis concentrates consumers likely develop a tolerance over time; that there may be genetic or biological differences that make some people metabolize THC more quickly; and that once cannabinoids fill receptors in the brain that spark intoxication, additional cannabinoids have little impact.