Feeling Depressed? Your Smartphone Detects It

Spending most of your time at home on your smartphone could signal depression.

In a recent study, GPS and usage sensor data from smartphones detected depressive symptoms with 87% accuracy.

Forty adults participated in the 2-week study, during which they carried around a mobile phone with a sensor data acquisition app called Purple Robot. All participants completed a self-reported depression survey before the study began.

Of the 40 participants, 28 ended up collecting enough sensor data to analyze.

The researchers found several markers of depressive symptoms in the GPS data, including circadian movement; “normalized entropy,” or mobility between the participants’ favorite locations; and location variance, meaning GPS mobility independent of location.

Subjects who stayed at home more or visited fewer locations were more likely to be depressed. This behavior could be a sign of a lack of motivation, the researchers noted. Not having a daily routine was also associated with depressive symptoms in the study.

Frequent smartphone usage also correlated with depressive symptom severity. Those who self-reported depression spent an average of about 68 minutes on their phone each day, while those without depressive symptoms used their phones for around 17 minutes a day, on average.

Based on these findings, the researchers posited that the more time subjects used their phone, the more likely they were to be depressed.

“The significance of this is we can detect if a person has depressive symptoms and the severity of those symptoms without asking them any questions,” said senior study author David Mohr, director of the Center for Behavioral Intervention Technologies at Northwestern University Feinberg School of Medicine, in a press release. “We now have an objective measure of behavior related to depression, and we're detecting it passively. Phones can provide data unobtrusively and with no effort on the part of the user.”

The authors noted that these tools could help identify patients at risk of depression and connect them with health care professionals.

“While these findings must be replicated in a larger study among participants with confirmed clinical symptoms, they suggest that phone sensors offer numerous clinical opportunities, including continuous monitoring of at-risk populations with little patient burden and interventions that can provide just-in-time outreach,” the researchers concluded.

Their findings were published on July 15, 2015, in the Journal of Medical Internet Research.