The Black Box: How Your Phone Can Tell That You're Depressed

A man wearing a replica of an iPhone 6 Plus model on his head yawns while waiting for the release of Apple's iPhone 6. A new study from Northwestern University links smartphone use and depression. Yuya Shino/REUTERS

You may know the feeling. It's the late afternoon, and you still haven't left the house. You've spent the last several hours on your phone, scrolling through your Facebook news feed, refreshing Twitter and watching YouTube videos. A smartphone might feel like it's keeping you connected, but it can also be a way of secluding yourself.

Data from a recent study conducted by researchers at Northwestern University's Feinberg School of Medicine found that the scenario described above—high volume of phone use and a static geographic location—could be linked to depression. The study, published in the Journal of Medical Internet Research, also found that depressed people, on average, spend more time on the phone than non-depressed people.

"People are likely, when on their phones, to avoid thinking about things that are troubling, painful feelings or difficult relationships," said David Mohr, one of the study's senior authors and a professor of behavioral psychology at Northwestern, in a statement. "It's an avoidance behavior we see in depression." Mohr also pointed out that depressed people tend to withdraw emotionally and avoid going out—behaviors that are arguably facilitated by the constant entertainment stream available on smartphones.

The study's participants consisted of a mix of people with and without prior depression. They completed a questionnaire describing their symptoms before agreeing to have their phone use monitored for two weeks. Using GPS, the researchers tracked their location and the amount of time they spent on the phone. They were then able to identify which participants were depressed using the aggregated phone data, with 87 percent accuracy.

Sohrob Saeb, a research fellow at Northwestern, said in the release that phones could be more reliable for diagnosing depression than traditional methods. In standard industry practice, patients are often asked to describe their symptoms by indicating how sad they are on a scale of 1 to 10. According to Saeb, the release reported, these responses can be rote and unreliable.

In contrast, the study found, a smartphone can unobtrusively and accurately measure a patient's daily activity, providing data that could trigger a health care provider to recognize the need for an intervention.

The study and its related press release, it should be noted, do not argue that high-volume smartphone use causes depression—only that there is a likely correlation. Future research at Northwestern, Saeb said in the release, will focus on whether encouraging patients to change their phone use behavior can lead to improvements in mood.