Medtronic is collaborating with Australian medtech company Medibio on a
non-invasive, wearable device-based solution to diagnose depression and
other mental conditions using electrocardiogram (ECG) and circadian
heart rate variability analysis.
http://www.meddeviceonline.com/doc/medtronic-announces-foray-into-wearable-tech-for-mental-health-0001