Can your phone tell when you’re high?
That’s the question researchers at Rutgers University set out to answer. What they found is that a phone’s sensors and GPS data can pick up movement changes that may indicate a person has used marijuana.
According to the preliminary study published in the journal Drug and Alcohol Dependence, smartphone data can detect with 90% accuracy if a person is experiencing cannabis intoxication.
The findings could have public safety implications. Currently, there is no clinically accepted way to test a person for cannabis intoxication. Blood and urine tests detect the presence of THC, the active ingredient in marijuana that produces a high feeling, days or weeks after a person has consumed.
This creates a problem enforcing driving under the influence laws. In New Jersey, police officers must be specially trained to recognize signs of impairment and couple them with a drug test to bring DUI charges. Efforts to get THC breathalyzers widely accepted and on the market have languished, as experts and law enforcement officials remain hesitant about the new technologies.
It’s too soon to say that smartphones will curb drugged driving. But the Rutgers research could lay the groundwork for phone alerts that would nudge a person, noting they may be impaired and should not drive or engage in other potentially dangerous activities.
“A lot of this is just trying to raise someone’s awareness and provide a friendly check-in,” said Tammy Chung, professor of psychiatry and director of the Center for Population Behavioral Health at the Rutgers Institute for Health, Health Care Policy and Aging Research, and an author of the study
“We did not do an intervention component, but that piece of it would need to be thought through very carefully and in partnership and with a lot of collaboration with stakeholders to make sure that it meets all of that people’s needs,” she said.
Looking at the time and day of the week gave researchers a 60% accuracy to detect whether a person was high. Adding smartphone sensor data bumped that figure to 90%.
The study focused on people who use cannabis at least twice a week. To expand the findings in future studies, researchers could focus on those who use marijuana less frequently.
But it’s also important to develop tools that can measure actual cannabis impairment in someone’s body, Chung said.
“I think the first thing is to try to replicate these results in a larger sample,” she said. “One of the most important things, is to find that biological marker of cannabis intoxication and impairment. That’s the critical piece. I don’t know how far that will be on the horizon.”
