Study identifies potential test for cannabis impairment

(Via The Harvard Gazette) Researchers at Massachusetts General Hospital found a noninvasive brain imaging procedure to be an objective and reliable way to identify individuals whose performance has been impaired by THC, the psychoactive ingredient in cannabis.

The technique uses imaging technology known as functional near-infrared spectroscopy (fNIRS) to measure brain activation patterns that correlate to impairment from THC intoxication, and this procedure could have significant implications for improving highway and workplace safety.

“Our research represents a novel direction for impairment testing in the field,” says lead author Jodi Gilman, an investigator in the Center for Addiction Medicine, MGH, and associate professor of psychiatry at Harvard Medical School. 

THC has been shown in past studies to impair cognitive and psychomotor performance essential to safe driving, a factor thought to at least double the risk of fatal motor vehicle accidents. The challenge for scientists, however, is that the concentration of THC in the body does not correspond well to functional impairment. One reason is that people who use cannabis often can have high levels of THC in the body and not be impaired. Another is that metabolites of THC can remain in the bloodstream for weeks after the last cannabis use, well beyond the period of intoxication. Hence the need for a different method to determine impairment from cannabis intoxication. Read the full article here, and access the full study here.