What are the trends in studies of blue and green spaces on mental health?

Abstract

This literature review investigates the trends between blue and green spaces and mental health from 2018 to 2024, aiming to address the gap in how specific features of these environments impact mental health or well-being. A systematic database search was done and 40 articles were selected after conducting a quality assessment. A thematic analysis was done combining both primary and secondary research and eight core themes were found. The results show that 22 articles are positively associated with mental health or well-being, while the other 18 articles indicated mixed relationships. In the results section, the articles were separated by primary and secondary sources, where positive and negative trends were identified. The positive trends in the primary sources included benefits from frequent or prolonged exposure, positive psychological outcomes, proximity and accessibility; distinct areas of green space correlate with well-being; reduced stress, depression, and medication use; and as well as, biodiversity and species richness. Negative trends included certain characteristics of green and blue spaces; no clear relationship; socioeconomic and environmental factors; and limitations of biodiversity or species richness. In contrast, all secondary research articles reported positive trends that include green spaces improving mental health and well-being, blue spaces providing restoration, stress reduction, and mental health benefits; and biodiversity improving mental health.