If you lose your smartphone and it happens to fall into the hands of Northwestern University scientists, they'd likely be able to figure out how depressed you are. Those researchers are reporting on the results of a small study in which they used smartphone "sensor data" to discern just that. The researchers came to their conclusion by looking at total phone usage, the number of locations visited per the phone's GPS, and the daily schedule recorded by such tracking over a 14-day period. The 28 participants also completed a standardized questionnaire designed to gauge depression. Half exhibited mild to severe depression, and half did not, and the researchers say they were able to accurately predict which smartphone owners had depressive symptoms 86.5% of the time.
In the usage category, those who weren't depressed logged about 17 minutes of usage, compared to an average 68 minutes among the depressed set. As for how GPS factors in, those who less frequently ventured beyond home were more likely to be depressed, as were those who didn't tend to have a recurring routine (ie, leaving for work at the same time daily). That's not too surprising: Lead author David Mohr explains in a press release that "when people are depressed, they tend to withdraw and don't have the motivation or energy to go out and do things." What was potentially more surprising is that the data "was more reliable in detecting depression" than the questions the participants answered, potentially providing a passive, unobtrusive way to detect depression. The study, published today in the Journal of Medical Internet Research, notes the findings "must be replicated in a larger study among participants with confirmed clinical symptoms."