Scientists want to clear the air on how THC alters basic motor functions
Researchers at the Yale Schoool of Medicine recently conducted a test to determine how THC can affect motor skills. While the study isn’t unique – many similar tests have already been realized – their format was. They intravenously gave cannabis to the subjects, instead of having them consume it through smoking or vaping.
23 recruits participated in the study. The scientists administered high- and low-THC infusions on the subjects before asking them to participate in several psychomotor tests. The results were similar to the results of previous studies, which have shown that THC infusion can result in “robust and significant deficits in motor performance,” depending on the dosage.
In one particular test, participants had to recognize a numeric sequence and press a response pad. The test showed that there was no significant performance difference between the subjects who had been administered THC and those who hadn’t. However, when tested against different levels of THC, those who had been administered a higher dose (0.03 mg/kg) demonstrated worse performance than those who had been given a low dose (0.015 mg/kg).
The study also produced an interesting, unexpected result. According to the researchers, “Perhaps even more concerning is the fact that even though the high dose of THC produced greater psychomotor deficits, subjects were not able to distinguish between levels of intoxication across the low- and high-dose conditions. This suggests that it may be difficult for individuals to gauge their level of psychomotor impairment based upon subjective feelings of intoxication, which could lead to greater risk during psychomotor-dependent behaviors.”
The study didn’t take into account a large set of variables. For example, it only concentrated on THC without the introduction of cannabinoids. Additionally, all of the subjects had abstained from cannabis use for at least three months prior to the test. The results were more than likely enhanced more than if the test had been administered to frequent users.
Researchers added, “These limitations notwithstanding, to our knowledge, this is the first controlled study examining a range of psychomotor functions in humans during the administration of several doses of IV THC. These results suggest that THC exhibits robust effects on fine motor control and motor timing in a dose-dependent manner, which have implications for real-world psychomotor-dependent behaviors such as driving, weapon use, operating machinery, work-related tasks, and skilled labor.”