Momentary associations between time-varying social contacts and depressive symptomatology in older adults: A GPS-based mobility survey study.

Studies often investigate the long-term impact of social contacts on mental health in older adults, neglecting momentary effects. This research, grounded in the consideration of daily activity, explores how time-varying social contacts associate with momentary depressive symptoms among 216 older adults in the Île-de-France region. Employing a geographically-explicit ecological momentary assessment approach (GEMA), we collected participants' depressive symptoms, mobility locations, and social contacts data via smartphone surveys, GPS receivers, and mobility survey over 7 days. Bayesian mixed models with random effects at individual and daily levels, considering time autocorrelation, were employed. Participants engaging with social contacts exhibited lower depression not only immediately but also in the following hours. Interestingly, a longer duration of time spent with social contacts did not lead to a sharper decrease in depression levels. Notably, larger decreases were observed when the number of social contacts increased from one to two, especially with friends or family members.