智能手机能诊断抑郁症了？

或许你可以强颜欢笑，但是你的手机会知道你是不是真心的。现在美国西北大学的研究者在研究利用智能手机来诊断抑郁症的方法。通过长期分析手机使用时间与手机携带者的日常活动地点等数据，可以判断手机携带者手否换上了抑郁症，准确率达到87%。

采用这种方式来诊断抑郁症，比问表式方法的好处是更客观，因为抑郁症患者很可能在问表诊断时不能正确评估自己的状态或者故意填错。

研究结果显示，长时间使用手机的用户易患抑郁症，活动地点少的用户也易患抑郁症。对于手机重度用户来说，真是难以取舍，好消息是手机可以诊断抑郁症了，坏消息是你要不要用来诊断一下？

You can fake a smile, but your phone knows the truth. Depression can be detected from your smartphone sensor data by tracking the number of minutes you use the phone and your daily geographical locations, reports a small Northwestern Medicine study.

The more time you spend using your phone, the more likely you are depressed. The average daily usage for depressed individuals was about 68 minutes, while for non-depressed individuals it was about 17 minutes.

Spending most of your time at home and most of your time in fewer locations -- as measured by GPS tracking -- also are linked to depression. And, having a less regular day-to-day schedule, leaving your house and going to work at different times each day, for example, also is linked to depression.

Based on the phone sensor data, Northwestern scientists could identify people with depressive symptoms with 87 percent accuracy.

"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 author David Mohr, director of the Center for Behavioral Intervention Technologies at Northwestern University Feinberg School of Medicine. "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 research could ultimately lead to monitoring people at risk of depression and enabling health care providers to intervene more quickly.

The study will be published July 15 in the Journal of Medical Internet Research.

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. Their 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."

While the phone usage data didn't identify how people were using their phones, Mohr suspects people who spent the most time on them were surfing the web or playing games, rather than talking to friends.

"People are likely, when on their phones, to avoid thinking about things that are troubling, painful feelings or difficult relationships," Mohr said. "It's an avoidance behavior we see in depression."

Saeb analyzed the GPS locations and phone usage for 28 individuals (20 females and eight males, average age of 29) over two weeks. The sensor tracked GPS locations every five minutes.

To determine the relationship between phone usage and geographical location and depression, the subjects took a widely used standardized questionnaire measuring depression, the PH