Connecting through nature: A systematic review of the effectiveness of nature-based social prescribing practices to combat loneliness

Loneliness is increasingly recognized as an urgent public health issue due to its impact on mental and physical health, and well-being. Yet, we lack comprehensive, proven strategies for confronting this global problem. There is evidence that contact with nature and greenspace reduces loneliness by facilitating belonging, social connections, and social cohesion. This review aimed to explore whether such positive outcomes can be enhanced via group-based interventions in nature. We used a mixed-methods systematic review approach to evaluate and characterize literature on nature-based social interventions for their effectiveness in reducing loneliness. We included all age groups, in populations with or without reported health problems. Using the Mixed Methods Appraisal Tool, we assessed the quality of included qualitative, quantitative and mixed methods studies. The 38 studies identified describe a wide variety of interventions and target groups. The quantitative studies included mostly small sample sizes with small or moderate effects. The qualitative studies, however, showed more clearly that these interventions can reduce loneliness. Group-based activities including natural elements cultivated connectedness and belonging, which are key mechanisms to reducing loneliness. Specifically, longer interventions showed greater promise. Policy and practice recommendations include loneliness screening, the need to describe loneliness more precisely, and the need to evaluate intervention effectiveness over time. This review provides perspectives to inform policymakers, urban planners, and researchers on how group-based interventions in nature can alleviate feelings of loneliness. By linking landscapes with public health concerns, municipalities can further promote and amplify the value of urban nature to the public.