Abstract
BACKGROUND: Digital assessment of behaviours, including physical activity, sleep, and social interactions could be associated with changes in mood and other mental health symptoms. This study assessed the safety, feasibility, acceptability, and potential predictive value of passive and active sensing in young people with major depressive disorder (MDD). METHODS: Over eight weeks, passive (smartphone sensing, actigraphy) and active (ecological momentary assessment; EMA) data were collected from 40 young participants with MDD (aged 16-25 years). We assessed the safety, feasibility, and acceptability of daily active and passive sensing in this population. Additionally, linear mixed models and correlation analysis explored associations between passive and active sensing measures. RESULTS: Of the 48 young participants, 83% (n = 40) completed the full protocol. No adverse events were reported. Over eight weeks, participants averaged 35.9 days (65.3%) with EMAs and 37.9 days (69%) with actigraphy data. Smartphone sensors recorded communication for 21.1 days (38.4%), location for 43.1 days (78.4%), maximum unlock duration for 43.4 days (79%), social media use for 34.8 days (63.3%), and inter-key delay for 32.8 days (59.6%). Regarding acceptability, 83.1% found the application usable and comfortable. Secondary measures showed significant correlations between sleep and physical activity, and between location and phone use sensors. There was a significant negative association between daily positive mood ratings and QIDS total scores (Beta coefficient [95% CI]: 2.66 [-3.98, -1.34]; p = 0.002). CONCLUSION: Passive and active sensing methods were safe, and acceptable among young people with MDD.