Depressed individuals spend three times longer on their phone.
We have previously reported on the impressive feats achieved by smartphones, including diagnosing blood parasites and reducing levels of anxiety. Now, scientists believe they can use the device to identify people suffering depressive symptoms with 87% accuracy.
The findings, published in The Journal of Medical Research, ultimately could assist with the monitoring of individuals at risk of depression, enabling health care providers to act more quickly.
Researchers from the Behavioral Intervention Technologies at the Northwestern University Feinberg School of Medicine in Chicago, IL, used an app to gather data from participants' smartphones.
Analyzing the data, the researchers found that those spending the most time on the phone were more likely to display symptoms of depression. The research also revealed spending most of your time at home - or in fewer locations - was also linked to illness. Having a less regular day-to-day schedule was also a factor.
Depression causes a constant feeling of sadness and lack of interest. Official figures for the illness are hard to predict, but a 2010 CDC study estimated that 1 in 10 Americans showed signs of depression.
The illness can be hard to treat as sufferers, more often than not, isolate themselves or refuse to acknowledge their feelings. Senior author, David Mohr, PhD, believes the results are an important development in understanding depression. He explains:
"The significance of this is that we can detect if a person has depressive symptoms and the severity of those symptoms without asking them questions."
Lead author, Sohrob Saeb, PhD, echoed this view. Saeb confirms the phone data was more reliable in detecting depression than daily questions participants answered about how sad they were feeling on a scale.
Each participant was asked to complete an online questionnaire consisting of demographic questions and a Patient Health Questionnaire-9 (PHQ-9) at the beginning of the study. The latter is commonly used to measure the severity of self-reported depressive symptoms. The most common symptoms of depression, such as sadness, changes in appetite and disturbances in sleep, are touched upon in the PHQ-9.
Depressed people use phone three times more than people who are not depressed
The 'Purple Robot' app used in the study tracked Global Positioning System (GPS) locations and phone usage data over 2 weeks. Dr. Saeb correlated this data with the subjects' test results to determine a relationship between phone usage, geographical location and depression.
From the 40 participants originally selected, only 28 were considered for data analysis. The other 12 did not produce sufficient sensor data. The results from the 28 found exactly half did not have any signs of depression, and half showed symptoms of mild to severe depression.
Results revealed those showing signs of depression tended to use their phone three times more compared to nondepressed participants. The average daily usage for the former was 68 minutes, compared with 17 minutes for the latter.
Also, depressed participants mostly stayed at home or traveled to fewer locations. Dr. Mohr explains: "When people are depressed, they tend to withdraw and don't have the motivation or energy to go out and do things."
Although the data traced did not identify how people were using their phones, Dr. Mohr believes participants were not talking to their friends but instead were avoiding thinking about stressful or painful feelings. He says that this "avoidance behavior" is commonly found in depression.Dr. Saeb hopes the data can be used to explore how better to diagnose the illness. He says: "The information could ultimately be used to monitor people who are at risk of depression, and to perhaps, offer them interventions if the sensor detected depression or to deliver the information to their clinicians." The next step for the team will follow on this research and see if any changes in behavior linked with depression will improve their mood. Written by Peter Lam