By Jessica Wapner

Imagine an app or wearable device that could tell a day in advance that an at-risk individual would experience suicidal thoughts—and alert the person and their trusted contacts. That might soon be a reality, thanks to the nascent field of mood forecasting.

We've become used to fitness trackers and other electronic devices that monitor our physical activity, and now scientists say similar technology can be used to track our psychological health in ways never before possible.

By spotting early signs of emotional distress, the new apps and wearables could soon help preserve our mental well-being.

“We rely on patients to tell us how they feel, and we are beholden to that in making our decisions,” says Ipsit Vahia, a psychiatrist at McLean Hospital in Belmont, Massachusetts. But because it isn’t subject to the vagaries of our mood and our ability to assess our psychological state, technology could give doctors more reliable information.