Evaluating the Effectiveness of Mindfulness Practice Doses in the General Population Through Personalization—A Randomized Controlled Experiment

Abstract Objectives There is likely not a one-size-fits-all solution in mindfulness-based programs and practice. This study explored how personality traits may moderate the impact of a single shorter versus longer mindfulness practice compared to control. Method In a large international study involving 636 adults, participants completed personality and trait mindfulness measures and were randomly assigned to either a 5-min mindfulness practice, a 20-min mindfulness practice, or an active control activity. State mindfulness and affect were assessed pre- and post-intervention. Results Both mindfulness practice doses increased state mindfulness compared to control, with longer sessions enhancing decentering. Contrary to hypotheses, neuroticism, conscientiousness, and openness to experience did not interact with mindfulness practice dose to produce differential outcomes. However, agreeableness did moderate dose-response effects: for those lower in agreeableness, a shorter mindfulness practice showed a significantly stronger decrease in negative affect compared to those higher in agreeableness. Similarly, trait mindfulness affected dose-response effects. Conclusions While single-session mindfulness practices are broadly beneficial, the most effective dose varies with agreeableness and trait mindfulness. This could support the personalization of brief, self-help mindfulness programs to increase benefits and cost-effectiveness across different individuals. Preregistration This research was prospectively registered on the Open Science Framework (ID: https://doi.org/10.17605/OSF.IO/VHUFT ) and the ANZCTR Clinical Trials (ID: ACTRN12624000599572) registration sites.