Associations Between Biodiversity-Related Exposures and Mental Health: A Scoping Review

Mental disorders are a leading cause of global disability, and environmental characteristics are increasingly recognized as relevant to mental health. Although green-space exposure has been associated with psychological benefits, the contribution of biodiversity-related exposures remains insufficiently characterized. This scoping review mapped quantitative associations between biodiversity-related exposures and mental health. Following PRISMA-ScR guidance, PubMed (MEDLINE), PsycINFO, and Embase were searched without date restrictions, supplemented by reference screening. English- or French-language quantitative studies were included when biodiversity was assessed using direct objective indicators, perceived biodiversity, or biodiversity-related ecological proxies and mental health outcomes were reported. Twenty-eight studies published between 2007 and 2024 met inclusion criteria, encompassing observational, experimental, and quasi-experimental designs across several geographic regions. Biodiversity-related exposures were generally associated with greater psychological well-being, positive affect, and restoration, and with lower stress-related outcomes; some studies also reported fewer depressive and anxiety symptoms. Perceived biodiversity showed more consistent associations with psychological outcomes than direct objective measures. Evidence for physiological and clinical outcomes was limited, and no study used formal psychiatric diagnostic assessments. Overall, biodiversity-related exposures may be relevant to mental health, but heterogeneous measures and predominantly cross-sectional evidence limit causal inference and support the need for standardized metrics and longitudinal or experimental studies.