You Can Only Get So High, New Study Finds
The study from Colorado reports that higher levels of THC do not necessarily lead to higher levels of intoxication, a finding that has implications for roadside testing of drivers.
Consuming cannabis with a high level of THC does not result in greater levels of intoxication, according to new research from the University of Colorado. In other words, you can only get so high.
The researchers looked at the neurobehavioral impairment of 121 cannabis users. Some smoked cannabis flower, others used concentrates. The researchers then compared impairment based on the levels of THC consumed.
The levels differed dramatically. For concentrates, researchers measured those who used products containing 70 percent to 90 percent THC. The flower products contained 16 percent and 24 percent THC. But no matter which they used, the study participants shared one thing in common: They all had similar “neurobehavioral patterns” and issues in the “domains of verbal memory and proprioception-focused postural stability," referring to one's ability to talk, walk, and stand.
The researchers concluded: “Differences in short-term subjective and neurobehavioral impairments did not track specifically with the strength of the cannabis consumed.” It wasn’t what they expected.
“Surprisingly, we found that potency did not track with intoxication levels,” Cinnamon Bidwell, lead author on the new study, told New Atlas. “While we saw striking differences in blood levels between the two groups, they were similarly impaired.”
The study findings could have big implications for law enforcement.
Law enforcement has been engaged for some time in trying to find a way to set a legal limit on how much cannabis a person can consume and then drive without breaking the law. So far, the focus has been on doing it by measuring the level of intoxicants in the bloodstream. This is how it is done with alcohol.
However, the study’s findings suggest cannabis doesn’t work like alcohol, with no association between blood levels of THC and intoxication.
The study found that everyone involved with the test felt similar feelings of intoxication, a self-assessment backed up by their similar performance on cognitive and balance tests. That included an 11 percent increase in “sway” by all participants shortly after consumption.
Researchers speculated that at some point, cannabinoid receptors in the body become saturated with THC and additional THC has no impact.
This already is becoming an issue, even with CBD products.
Federal regulators already have started to warn commercial drivers about the use of hemp-derived CBD products. Although they contain little to no traces of CBD, some products have more than drivers might expect.
The federal Department of Transportation has warned drivers that they could fail drug tests if they use CBD products that contain trace amounts of THC. They also note that “the Food and Drug Administration (FDA) does not currently certify the levels of THC in CBD products, so there is no federal oversight to ensure that the labels are accurate.”
Establishing a level of THC in the bloodstream that makes someone incapable of driving will likely prove extremely difficult. As noted in a Congressional Research Services report, THC does not act like alcohol. Alcohol depresses and slows down the nervous system. It’s also quickly absorbed into the bloodstream. THC, on the other hand, impacts the body in more complex ways and the full effects are often not felt right away.
The results of the University of Colorado study will add more fodder to the debate over how to blood test cannabis-influenced drivers, or whether such a test is even possible.