As the movement to legalize marijuana in the United States gains momentum, researchers worry about keeping the public safe, particularly on the roads.
Recent studies in which marijuana users took controlled doses of cannabis in the lab have identified new biomarkers that can be used to estimate a person's recent cannabinoid intake, according to Science Daily. But, using those markers to judge cognitive and behavioral impairment is complex, say toxicologists in a commentary published on January 25 in a special issue of the journal Trends in Molecular Medicine on biomarkers of substance abuse.
"There is no one blood or oral fluid concentration that can differentiate impaired and not impaired," says Marilyn Huestis, who spent over 20 years leading cannabinoid-related research projects at the National Institute on Drug Abuse. "It's not like we need to say, 'Oh, let's do some more research and give you an answer.' We already know. We've done the research."