Researchers at Dartmouth have created an app smart enough to know the users state of mind - even if they don't, according to a recent study.

The StudentLife app reveals students' mental health, academic performance and behavioral trends. It compares students' happiness, stress, depression and loneliness to their academic performance, also may be used in the general population -- for example, to monitor mental health, trigger intervention and improve productivity in workplace employees.

"The StudentLife app is able to continuously make mental health assessment 24/7, opening the way for a new form of assessment," Andrew Campbell, senior author of the study and a computer science professor, said in a statement. "This is a very important and exciting breakthrough."

The researchers built an Android app that monitored readings from smartphone sensors carried by 48 Dartmouth students during a 10-week term to assess their mental health (depression, loneliness, stress), academic performance (grades across all their classes, term GPA and cumulative GPA) and behavioral trends (how stress, sleep, visits to the gym, etc., change in response to college workload -- assignments, midterms, finals -- as the term progresses).

They used computational method and machine learning algorithms on the phone to assess sensor data and make higher level inferences (i.e., sleep, sociability, activity, etc.) The app that ran on students phones automatically measured the following behaviors 24/7 without any user interaction: sleep duration, the number and duration of conversations per day, physical activity (walking, sitting, running, standing), where they were located and how long they stayed there (i.e., dorm, class, party, gym), stress level, how good they felt about themselves, eating habits and more. The researchers used a number of well known pre- and post-mental health surveys and spring and cumulative GPAs for evaluation of mental health and academic performance, respectively.

The results show that passive and automatic sensor data from the Android phones significantly correlated with the students' mental health and their academic performance over the term.

Campbell says the smartphone app raises major privacy concerns, but with proper protections in place, the app can provide continuous mental health evaluation for people from all walks of life rather than waiting for symptoms of stress and depression to become severe enough to visit the doctor.

The researchers presented their findings on Wednesday at the ACM International Joint Conference on Pervasive and Ubiquitous Computing.