Digital mandala coloring as a public mental health tool: psychophysiological benefits and the mediating role of flow in anxiety reduction among university students.

Background: Anxiety is becoming more common among young people globally. At the same time, digital mental health services are developing rapidly. Digital mandala coloring applications have become popular tools for managing anxiety. However, it remains unclear if they are effective as psychological tools, and their mechanism of action lacks scientific verification. This study aims to investigate the effectiveness of digital mandala coloring in relieving anxiety and the role of flow in its mechanism. Methods: This study involved 60 university students across two experiments employing coloring intervention using physiological and psychological measurements. Experiment 1 compared the differences in anxiety relief and level of flow state between digital and traditional paper-based mandala coloring. Experiment 2 further explored the impact of two mainstream interaction modes, sliding coloring and gamified coloring, in digital mandala coloring on user experience and therapeutic effect. All participants underwent anxiety induction before a 30-min coloring activity. State anxiety and physiological indicators were measured at baseline (T1), after anxiety induction (T2), and after the coloring intervention (T3). Flow state level was measured at T3. Results: Digital mandala coloring demonstrated efficacy in reducing self-reported state anxiety, with no significant difference to the traditional method. However, it induced a higher level of flow state and demonstrated stronger physiological calming effects, specifically greater reductions in heart rate and skin conductance level. Experiment 2 indicated that, compared to the gamified coloring condition, sliding digital mandala coloring led to greater anxiety reduction, a higher level of flow state, and more pronounced improvements in heart rate and skin conductance level recovery. Crucially, the flow state was found to fully mediate the relationship between the digital coloring mode and state anxiety level. These results suggest that the anxiety-reducing effect of digital mandala coloring can be enhanced by increasing immersion and fostering flow. Conclusion: Digital mandala coloring is an effective anxiety intervention for university students. Its therapeutic effect can be significantly enhanced by interaction designs that improve operational fluency, as such designs promote a deeper flow state. This study provides a key insight for developing digital mental health applications: optimizing interactive fluency to promote immersive flow experience is more important than pursuing entertainment for enhancing emotional healing value. This finding points the way for applying and developing digital interventions in public health.