Researchers at Massachusetts General Hospital (MGH) have found a non-invasive brain imaging procedure to be an objective and reliable way to identify individuals whose performance has been affected by THC, the psychoactive component in cannabis. The technique uses an imaging technique known as functional near-infrared spectroscopy (fNIRS) to measure brain activation patterns related to impairment from THC intoxication. As reported in the journal neuropsychopharmacology, The process could have important implications for improving highway and workplace safety.
The increasing use of cannabis through legalization has created an urgent need for a portable brain imaging procedure that can differentiate between harm and mild intoxication from THC. “Our research represents a novel direction for harm testing in the field,” says lead author Jodi Gilman, PhD, investigator at the Center for Addiction Medicine, MGH. “Our goal was to determine whether cannabis impairment could be detected by brain activity at the individual level. This is an important issue as a ‘respiratory’ type approach would not work for detecting cannabis harm.” , making it very difficult to objectively assess the harm from THC during traffic stops.”
THC has been shown in previous studies to reduce cognitive and psychomotor performance required for safe driving, a factor thought to at least double the risk of fatal motor vehicle accidents. However, the challenge for scientists is that the concentration of THC in the body does not correspond to functional impairment. One reason is that people who use cannabis can often have high levels of THC in their bodies and may not go bad. The second is that metabolites of THC can remain in the bloodstream for weeks after the last cannabis use, beyond the duration of intoxication. Therefore a different method is needed to determine the harm caused by cannabis intoxication.
In the MGH study, 169 cannabis users underwent fNIRS brain imaging before and after receiving either oral THC or placebo. Participants who reported intoxication after being given oral THC had an increase in oxygenated hemoglobin concentration (HbO) — a type of neural activity signature from the prefrontal cortex area of the brain — compared to those who received little or no intoxication. Told.
Founding director of the Center for Addiction, senior author and principal investigator A. “The identification of acute impairment from THC intoxication via portable brain imaging could be a valuable tool in the hands of police officers in the field,” explains Eden Evins, MD, MPH. Medicine. “The accuracy of this method was confirmed by the fact loss determined by the machine learning model, which corresponds to a self-reported and clinical assessment of 76 percent impairment, using only information from the fNIRS.”
Although the study did not specifically assess FNIRS in roadside assessments of poor driving, it cited considerable advantages for such an application. These include the viability of cheap, lightweight, battery-powered fNIRS devices that allow data to be either stored on wearable recording units or transmitted wirelessly to laptops. In addition, fNIRS technology can be incorporated into headbands or caps, and thus requires minimal set-up time.
“Companies are developing breathing devices that only measure cannabis exposure, but not the harm caused by cannabis,” says Gilman. “We need a method that does not punish medical marijuana users or others with insufficient amounts of cannabis in their systems to impair their performance. Although this requires further study, we believe.” that brain-based testing may provide an objective, practical and much-needed solution.”
Gilman is an associate professor of psychiatry at Harvard Medical School. Evins is the Cox Family Professor of Psychiatry at Harvard Medical School.
The study was funded by the National Institute on Drug Abuse.
material provided by Massachusetts General Hospital, Note: Content can be edited for style and length.