Could a smart watch act as an early‑warning system for depression relapse? New research from McMaster University suggests that disruptions in a person's sleep and daily activity routine, as detected through a simple wrist-worn device, can signal when there is increased risk of relapsing into major depression.
The new research highlights a simple, yet powerful way to passively monitor relapse risk in people living with major depressive disorder (MDD), often detecting the probability of a relapse weeks or months before the episode occurs. Approximately 60 per cent of people with MDD relapse within five years, even with treatment.
"Advances in digital technology and AI algorithms have a great potential for relapse prevention in mental health. Imagine a future where a smartwatch can warn people with depression: 'A new episode of depression is very likely coming within the next four weeks. How about seeing your health-care provider?'" says Benicio Frey , professor in the Department of Psychiatry and Behavioural Neurosciences at McMaster.
The study, published in JAMA Psychiatry on Feb. 11, 2026, followed 93 adults across Canada who had previously recovered from depression and wore a research-grade actigraphy device, similar to a Fitbit or Apple Watch. Participants wore the wearable device for one to two years, generating over 32,000 days of sleep and activity data.
Key findings:
- Individuals with a more irregular sleep profile had nearly double the risk of relapse.
- The strongest predictor of relapse was whether a person's body detected less difference between daytime activity and nighttime rest.
- How much time spent awake during the night after already falling asleep also predicted increased risk of depression relapse.
- Participants' sleep schedules became more erratic before a relapse took place.
This research underscores the untapped potential of wearable technology for people recovering from MDD because it collects data passively and could provide continuous insight between clinical appointments. Current monitoring relies heavily on symptoms, which usually appear later than what can be detected through a wearable device.
Researchers say there are opportunities for health system innovation, where wearable-derived alerts could help clinicians target care to those most at risk, improving outcomes and reducing the burden of recurrent episodes.
"While it has been long recognized that abnormal sleep and activity patterns are associated with greater risk of depression relapse, the ability to passively detect these abnormal patterns using smart sensors opens an exciting new window of opportunity for personalizing the care of conditions that may reoccur, like depression".
MDD is a common and serious medical condition that affects millions of people globally. Depression impacts how a person feels, thinks and functions, and can cause persistent symptoms like low mood, lack of appetite, feelings of guilt and loss of interest in activities.
The study was supported by the Ontario Brain Institute, Janssen Research & Development, and the Ontario Research Fund – Research Excellence, in partnership with the Canadian Biomarker Integration Network in Depression (CAN‑BIND).
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