Activating Social Resources in Psychotherapy-Seeking Individuals: Effectiveness and Timing of a Social Support Just-in-Time Adaptive Intervention

This study evaluates a Just-In-Time Adaptive Intervention (JITAI) aiming to foster social support processes for adults with elevated depressive symptoms awaiting outpatient psychotherapy. Utilizing a daily-level micro-randomized trial (MRT) design conducted over 21 days, participants are assessed six times daily. Participants are randomized across four conditions: (1) vulnerability-triggered, (2) vulnerability and receptivity-triggered, (3) support-need-triggered, and (4) a no-intervention control. The primary objective of this study is to evaluate the effectiveness of the JITAI in reducing daily depressive symptoms and increasing received social support (primary outcomes), as well as reducing daily loneliness and enhancing perceived social support (secondary outcomes). Furthermore, the study aims to compare the relative efficacy of three distinct triggering strategies to identify the most effective timing for intervention delivery.