Optimizing prompt frequency in a brief online emotion regulation training for community adults: A three-arm randomized controlled trial.

Background: Online emotion regulation interventions show promise for addressing mental health concerns, yet optimal delivery parameters remain unclear. This study aimed to (1) evaluate the efficacy of a brief online emotion regulation (ER) intervention against a robust active control, and (2) investigate the impact of practice prompt frequency on clinical outcomes. Methods: In this three-arm randomized controlled trial, community adults (N = 194) were randomly allocated to: emotion regulation training with three daily prompts (ER-TD), emotion regulation training with one daily prompt (ER-OD), or stress psychoeducation control (SPC). The 5-week intervention delivered evidence-based emotion regulation skills (awareness, acceptance, self-compassion, mindfulness, cognitive reappraisal) or educational content about stress. Assessments occurred at baseline, weeks 2 and 4, post-intervention, and 3-month follow-up. Primary outcomes were depression (CES-D) and perceived stress (PSS-10); secondary outcome was emotion regulation difficulties (DERS-18).Results: Participants in both ER conditions (ER-TD and ER-OD) demonstrated significantly greater improvements in depression, perceived stress, and emotion regulation difficulties compared to the SPC group at the end of training. Direct comparisons revealed no significant differences between the ER-TD and ER-OD groups on any outcome at the end of the intervention. However, at the 3-month follow-up, improvements in overall emotion regulation skills were sustained only in the ER-TD group. Conclusions: Brief online emotion regulation training effectively reduces depression and stress compared to a robust active control. While single daily prompts were sufficient for initial skill acquisition-suggesting a minimal effective dose for engagement-higher frequency supported superior long-term maintenance. These findings point toward adaptive implementation strategies: starting with lower-frequency prompts to reduce burden, then increasing frequency for skill maintenance.