This study explores the feasibility of using smile and smirk expression dynamics, captured through our novel stimulus-based mobile affective probe, as candidate digital biomarkers of depression severity within a large-scale mobile health intervention trial, BeWell.
Mixed-effects models reveal that higher maximum Duchenne smile intensity in reaction to liked stimuli is associated with lower depression scores over time at both within- and between-person levels.
We additionally share insights from our tool, including ease of use, perceptions of the stimulus, and technical challenges, which offer considerations for the future development of stimulus-based affect probes in real-world settings.