A New Study Suggests An Effective Replacement For Marijuana Breathalyzers

By Maria Loreto, The Fresh Toast on

Published in Cannabis Daily

Marijuana breathalyzers have long been in development, producing no fruitful results. A new study shows a different path.

Researchers have found a non-invasive way of determining whether or not a person has been impaired by THC. This discovery, achieved thanks to a study conducted by Massachusetts General Hospital and published in the journal Neuropsychopharmacology, could provide an answer for DUIs related to cannabis consumption, providing a pathway in treating these types of situations.

According to The Harvard Gazette, the technique used in the study is called functional near-infrared spectroscopy (fNIRS), which measures brain patterns, which researchers then correlated to THC impairment. The device in question would be designed to be portable and noninvasive, allowing people to use it on the go, measuring THC impairment in subjects.

The study had 169 cannabis users consume THC or a placebo and then submit themselves to fNIRS scans. Those who’d consumed cannabis showed higher levels of neural activity in the prefrontal cortex of the brain when compared to those who’d consumed a placebo.

“Our research represents a novel direction for impairment testing in the field,” said lead author Jodi Gilman, associate professor at Harvard and investigator in the Center for Addiction Medicine. “Our goal was to determine if cannabis impairment could be detected from activity of the brain on an individual level. This is a critical issue because a ‘breathalyzer’ type of approach will not work for detecting cannabis impairment, which makes it very difficult to objectively assess impairment from THC during a traffic stop.”

A cannabis breathalyzer has long been the gold standard that researchers have been working towards. A recent study showed how unhelpful these devices were in measuring THC impairment, particularly because they measure the presence of the compound in saliva, a connection that is inconsistent and not indicative of impairment while driving or operating some kind of machinery.


“Someone who’s experienced with cannabis might show the same levels of THC in their blood as someone who’s inexperienced with it. These two people will likely have completely different responses to the drug and how impaired they are by it,” the Fresh Toast reported in a previous article.

While further study is necessary for devising a product that’s capable of producing these scans on the go, this finding is a necessary first step for preventing roadside accidents and ensuring workplace safety.

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