Severity of Depression and Anxiety Symptoms is Reflected in Physiological and Behavioral Metrics Collected from a Consumer-Grade Wearable Ring

Background: Modern wearable devices generate a multitude of digital metrics, which can be used to measure human function in health and disease. This study investigated whether and how digital metrics generated from a consumer-grade smart ring were different in individuals with varying severity of depression and anxiety symptoms in a large population-based cohort. Methods: Cross-sectional data were obtained from the Northern Finland Birth Cohort 1986 when participants were 33-35;years of age. Participants were asked to wear the Oura Ring for two weeks, which provided digital measures of sleep architecture, nocturnal heart rate (HR), nocturnal heart rate variability indexed by the root mean square of successive differences between normal heartbeats (RMSSD), and minute-by-minute movement intensity. Participants with at least one weekday and a weekend day with no less than 15 hours of wear time were included. Two screening tools were used to assess depression and anxiety symptoms. Symptoms of anxiety were assessed using the Generalized Anxiety Disorder 7-item scale (GAD-7) and symptoms of depression and anxiety using Hopkins Symptom Checklist-25 (HSCL-25). Participants were grouped into no, mild, and moderate-to-severe anxiety symptom groups based on GAD-7, and with and without depression and anxiety symptoms based on HSCL-25. Time-series data were visualized, and statistical differences between groups were assessed using one-way ANCOVA followed by Tukey's post hoc test. Results: A total of 1,290 participants provided enough valid data and were included. Participants with moderate-to-severe anxiety assessed by GAD-7 and with depression and anxiety symptoms assessed by HSCL-25 exhibited lower percentage of rapid eye movement (REM) and deep sleep, and increased light sleep compared with the group without depression and anxiety. These two groups also showed higher HR, lower RMSSD during sleep, and lower levels of physical activity during the day. The differences between mild anxiety group with no and moderate-to-severe anxiety groups were overall less apparent on average. Conclusions: Findings suggest that severity of depression and anxiety can be reflected in behavioral and physiological metrics generated by a consumer-grade wearable ring. These findings suggest that they may be a promising tool for enhancing symptoms tracking and informing personalized care strategies.