Effectiveness of portable digital nature experience on mental health: A three-level meta-analysis of randomized...

Nature experience has substantial benefits for restoring mental health, but the accessibility of nature has hindered the scalability of this strategy. The Portable Digital Nature Experience (PDNE) could offer an alternative solution. A total of 118 effect sizes from 36 randomized controlled trials were included, involving 2925 participants across 17 countries and regions. Results from the three-level meta-analysis indicate that PDNE significantly reduced three common mental health issues, including stress (g = -0.51; 95% CI [-0.73, -0.28]; p < .001), anxiety (g = -0.67; 95% CI [-1.01, -0.33]; p < .001), and depression (g = -0.26; 95% CI [-0.51, -0.01]; p = .044). In terms of reducing stress, the green space intervention was significantly more effective than the mixed landscape intervention (p = .008). Regarding anxiety, the auditory condition yielded significantly better results than the multisensory (p = .021) and visual (p = .011) conditions. Similarly, for depression, the auditory condition was significantly more effective than the visual condition (p = .016), and the Active Control Group demonstrated superior outcomes compared to the Treatment As Usual Control Group (p = .028). No significant differences were found in sample characteristics (sex composition, age distribution, clinical status), intervention content (duration of intervention), or study characteristics (research context, measurement indicator, and measurement time). This study demonstrates that PDNE can be effective in alleviating mental health problems and has the potential for large-scale replication. In scenarios where nature experience is constrained, it is hoped that the benefits of PDNE will advance social equity.