A Social Support Just-In-Time Adaptive Intervention for Individuals with Elevated Depressive Symptoms: A Feasibility Study with Micro-Randomized Trial Design

Background: Just-In-Time Adaptive Interventions (JITAIs) aim to provide psychological support during critical moments in daily life. Objective: This preregistered study evaluated the feasibility of a social support JITAI for individuals with elevated depressive symptoms awaiting psychotherapy. Triggered by Ecological Momentary Assessment (EMA) reports, the intervention encouraged participants to activate their (digital) social support networks. Methods: Twenty-five participants completed 2,689 EMAs and received 377 JITAIs over an 18-day intervention period, including a micro-randomized trial design to compare four strategies to trigger an intervention: Fixed cutoff points of distress variables, personalized thresholds (through Shewhart Control Charts) of distress variable, momentary support need, and no intervention. Results: The results showed high feasibility, with participants completing 85% of EMA surveys, low study-related attrition rate (7%), and reporting minimal technical issues. Engagement and perceived helpfulness were heterogenous and moderate, with participants seeking support in one-third of triggered instances. JITAIs triggered by self-reported need for support were rated as more appropriately timed, helpful, and effective for promoting support-seeking behavior compared to those based on distress indicators, despite being triggered less frequently. Barriers such as time constraints and perceived unavailability of support providers likely affected support seeking behavior, as indicated by additional qualitative analyses. Exploratory effectiveness analyses indicate Cohen’s d effect sizes between 0.06 - 0.14 in reducing distress after JITAIs were received. Conclusion: These findings demonstrate that a social support JITAI is feasible to implement, with high compliance and minimal technical issues. Yet, further research is needed to evaluate the JITAI’s effectiveness and to optimize trigger strategies in addressing individual needs and barriers to engagement.