Is it possible that your phone knows more about what goes on inside you than you know about what goes on inside your phone? Well, according to a recent Northwestern Medicine study, depression can be detected from your smartphone sensor data, through following how many minutes you use the phone and your daily geographical locations.

Guess what? The more you use your phone, the more likely it is that you are depressed. Average daily usage for depressed people was around 68 minutes, but for non-depressed people it was about 17 minutes.

Staying at home most of the time, and spending most of the time in fewer locations, as tracked by GPS data, also are linked to depression.

Other factors that were linked to depression include having a less regular day-to-day schedule, for example, leaving your house and going to work at different times each day.

The researchers were able to identify people with depressive symptoms with 87 percent accuracy, based on the smartphone sensor data. So what, you ask?

Senior author David Mohr, director of the Center for Behavioral Intervention Technologies at Northwestern University Feinberg School of Medicine, said:

“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. 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 findings may ultimately lead to being able to monitor people at risk of depression and enable health care providers to intervene more quickly.

In fact, the smart phone data was more reliable in detecting depression than daily questions participants answered about how sad they were feeling on a scale of 1 to 10. Such answers may be rote and often are not reliable, said lead author Sohrob Saeb, a postdoctoral fellow and computer scientist in preventive medicine at Feinberg.

“The data showing depressed people tended not to go many places reflects the loss of motivation seen in depression,” said Mohr, who is a clinical psychologist and professor of preventive medicine at Feinberg. “When people are depressed, they tend to withdraw and don’t have the motivation or energy to go out and do things.”

Northwestern researchers will look, in the future, at whether getting people to change those behaviors linked to depression improves their mood.

“We will see if we can reduce symptoms of depression by encouraging people to visit more locations throughout the day, have a more regular routine, spend more time in a variety of places or reduce mobile phone use,” Saeb said.

Sohrab Saeb, Mi Zhang, Christopher J Karr, Stephen M Schueller, Marya E Corden, Konrad P Kording, David C Mohr Mobile Phone Sensor Correlates of Depressive Symptom Severity in Daily-Life Behavior: An Exploratory Study J Med Internet Res 2015 (Jul 15); 17(7):e175

Photo: Nicolas Nova/flickr

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