Smartphones can track fitness, sleep and nutrition, and they might be able to detect depression, too.
A small Northwestern Medicine study tracked the smartphone use and GPS locations of 28 adults, finding that the more time you spend using your phone and the fewer places you visit, the more likely you are to be depressed.
To collect their data, researchers first administered a standardized questionnaire that commonly measures depression symptoms to the participants. They found that half of the study participants did not have any signs of depression, and the other half had symptoms that ranged from mild to severe depression.
Then, the researchers used information collected from the participants' phone sensors over a two week period to see if depression scores matched the questionnaire. They tracked text messaging, app usage and location throughout the day. They also asked participants, via a daily pop up message, to rate their feelings of sadness on a scale of ten.
When they compared the scores to see how accurately the phone data mirrored the more traditional assessment tool, the researchers found that the sensor data could estimate depression scores with 87 percent accuracy.
What's more, tracking behavior via these sensors was more accurate at determining depression levels than the single daily question about mood.
The phone sensors showed that people who have a more irregular schedule -- like, say, leaving for work at 9 a.m. on one day and at 1 p.m. on another -- were more likely to be depressed, according Dr. Sohrob Saeb, the study's lead author and a research fellow at the Feinberg School of Medicine. Additionally, the GPS tracker linked depression with people who spent most of their time in one location, typically their homes.
Phone use behavior was also revealing: Depressed participants spent an average of 68 minutes on their phones each day, while non-depressed individuals averaged 17 minutes. Previous studies have found a link between excessive cell phone use with depression, stress and sleep issues, though more research is needed to understand the relationship, according to Saeb.
"The theories say that depressed people tend to have this 'avoidance behavior,'" Saeb told The Huffington Post. "In order to avoid actual situations and real things out there in the world, they distract themselves by using their phone."
This is not the first time researchers have used smartphones to track mental health. An app developed in 2014 by University of Michigan researchers, for instance, monitored vocal changes during phone conversations to detect mood swings in people with bipolar disorder.
Smartphone monitoring is attractive to clinicians who want more accurate and less invasive ways to monitor their patients. "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," said senior author David Mohr, director of the Center for Behavioral Intervention Technologies at Northwestern University Feinberg School of Medicine, in a statement.
"We can detect if a person has depressive symptoms and the severity of those symptoms without asking them any questions," he added.