Researchers have shown preliminary evidence that is possible to predict if someone is high on cannabis using smartphone sensors. The approach uses some data from the owner's smartphone to estimate if they have become intoxicated after consuming cannabis.
The study is published in the journal Drug and Alcohol Dependence and it is based on a survey of 57 young adults aged between 18 and 25 in Pittsburgh, Pennsylvania. The participants self-reported using cannabis at least twice per week, and the team used data from their mobile phones to see if this was enough to work out when people consumed the substance.
The accelerometer – the motion sensor within the phone – and GPS data were important features in detecting intoxication. Using just time features, such as day of the week and time of the day, the study was able to correctly identify 60 percent of the 451 cannabis use episodes. The accuracy climbed to 90 percent once time features, combined with smartphone sensor data, were included in the analysis.
"Using the sensors in a person's phone, we might be able to detect when a person might be experiencing cannabis intoxication and deliver a brief intervention when and where it might have the most impact to reduce cannabis-related harm," corresponding author professor Tammy Chung, from the Rutgers Institute for Health, Health Care Policy and Aging Research, said in a statement.
The approach is still a proof of concept but it does suggest that it is in principle feasible to use a phone sensor to detect cannabis intoxication, in a way that could be used for delivering timely interventions. It is known that smart technology can be little snitches if you let them, recording your location and activities. And it appears to be sensitive enough to actually determine some unusual behavior.
Smartphones have previously been used in a similar approach when it comes to drunkness. Although that test was conducted in the lab and not a more natural environment, the accelerometer was still able to pick up when a person had consumed alcohol over the legal driving limit in the United States about 90 percent of the time.
In the US, cannabis is illegal under federal law, although the medicinal use of cannabis has been legalized in 36 states, four out of five permanently inhabited U.S. territories, and Washinton DC. The recreational use of cannabis is legalized in 18 states, Washington, the Northern Mariana Islands, and Guam.
The war on cannabis, which cannabis is winning given the number of states and jurisdictions that have made it legal, remains deeply racialized against Black and Brown people who continue to be arrested at a higher rate than white people even in those states where the drug is legal.