Nature Scripts to Promote Social Sustainability: Monetizing Wellbeing Benefits of Group-Based Nature Exposure for Young Adults with Mild to Moderate Mental Illness

The mental health of young adults is a widespread and growing concern in many communities, impacting social sustainability. At the same time, there is growing evidence of the value that nature can provide towards improving health and wellbeing. However, there is little research on the scale of the monetized value of relevant wellbeing benefits from nature exposure. Nature prescribing draws on the growing base of evidence about nature and its health and wellbeing connections, with medical practitioners and/or allied health workers providing a prescription to selected patients to participate in a program that offers interventions intended to improve participant health and/or wellbeing, using a nature setting. This paper is the first to undertake a cost–benefit analysis of nature prescribing, involving a program aimed to improve the wellbeing of young adults with mild to moderate mental illness in regional/rural Victoria, Australia. The evaluation demonstrates that a curated, group-based nature exposure program can yield significant improvement in levels of life satisfaction and mental health in this cohort. Paired sample comparisons and multiple regression analyses suggest that the program produced an increase in mean participant life satisfaction scores of ~0.7 units, measured using Personal Wellbeing Index scores. A project benefit–cost ratio of over four resulted from this. Mental health, as measured by Kessler scale scores, also showed solid improvement, and loneliness was reduced. The unique contributions of nature and of the group-based delivery mode to the measured benefits were not identifiable but the combined effect was evident, improving participants’ likelihood of social inclusion, a major social sustainability goal. Furthermore, the solid program benefit–cost ratios indicate an economically sustainable program, which uses an environmental platform (nature) for its delivery. This links all three triple bottom line sustainability outcomes to this program. Topping up group-based nature exposure, after completion of the six-session, two-hours-per-session program, was important for many participants to sustain benefit levels. Participants emphasized the importance of the program being delivered by trained professionals. Achieving involvement of a suitably sized project comparison or control group through the 8-month program evaluation period to follow-up proved challenging, which somewhat weakens the power of the evaluation findings.