Smartphones have been used to track everything from the steps you take to the food you eat. Now, a small study from Northwestern University Feinberg School of Medicine in Illinois suggests cellphones might also be able to tell whether you're depressed.
The study released on Wednesday in the used information on the mobile usage and GPS locations of 28 participants for two weeks who had an average age of 29 years.
The 20 females and eight males performed a patient health questionnaire that measures depression at the beginning of the study, and also downloaded the app which collected their information.
The results showed that half of the participants had depressive symptoms ranging from mild to severe. Researchers found that those showing symptoms spent an average of 68 minutes on their phones, while those without symptoms would spend about 17 minutes.
Those with symptoms also spent most of their time at home or work and were less likely to have a routine daily schedule, said the study's senior author David Mohr, director of the Center for Behavioral Intervention Technologies.
"The data showing depressed people tended not to go many places reflects the loss of motivation seen in depression," Mohr said in a . "When people are depressed, they tend to withdraw and don鈥檛 have the motivation or energy to go out and do things."
Results 'should not be taken too seriously'
But a commentary on the website for says the study's results "should not be taken too seriously" because the sample size was too small and the authors hadn't properly taken into account several factors that may have affected the results.
"A major factor that was not accounted for was whether any of the people involved in the study were employed, the nature of the employment, or whether they were looking after children or caring for someone. This would have had a major impact on their phone use and the amount of time they spent going out to different places," the commentary reads.
As well, the authors didn't account for a history of mental health problems, or the medical or psychiatric conditions of the participants.
"In short, this study does not show smartphone use can diagnose depression."
Lead study author Sohrob Saeb said that until another study is conducted with more people over a longer period of time, readers shouldn鈥檛 draw any definitive conclusions.
鈥淚t鈥檚 an exploratory study,鈥� Saeb said in a phone interview with CTVNews.ca. 鈥淭wenty-eight people is definitely not enough to draw any definite conclusions.鈥�
But the study authors say the cellphone data they collected gave "more reliable" information for detecting depression than daily questions in which participants were asked how sad they felt on a scale of one to 10.
Using an algorithm developed by lead author of the study, Sohrob Saeb, the researchers achieved an 86.5 per cent accuracy rate for detecting depression by looking at cellphone use.
The researchers are now working on a study of 120 participants who have confirmed clinical depression, Saeb said. It will need to show the same results are achieved before drawing any firm conclusions, researchers said. If they are, Saeb believes using cellphones to detect symptoms of depression could help medical professionals intervene sooner in an objective and unobtrusive way.
"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.
The authors also hope to look at what participants are doing while on their phones. Mohr believes they are more likely to be surfing the web or playing games rather than interacting with friends or family.
"People are likely, when on their phones, to avoid thinking about things that are troubling, painful feelings or difficult relationships," he said. "It's an avoidance behaviour we see in depression."
