Study confirms green space dramatically improves mental health in urban areas
A large international study from Monash University found that increased exposure to green space in cities is associated with significantly fewer hospitalizations for mental health disorders among urban dwellers. The analysis, covering 11.4 million hospital admissions across seven countries over two decades, found a 7% overall reduction in hospital admissions for mental health issues. The findings underscore the importance of integrating nature into urban design as a critical public health strategy.
The daily pressures of city life, from work deadlines to family obligations, can severely impact mental well-being. Researchers at Monash University in Australia have identified a simple solution: integrating green space into urban environments can significantly improve the mental health of city dwellers. The study's findings point to nature as a potentially powerful public health prescription.
The large international study found that higher levels of "greenness" were consistently associated with fewer hospitalizations for mental health issues among urban dwellers. Analyzing data from 11.4 million hospital admissions for mental disorders across 6,842 locations in seven countries (Australia, Brazil, Canada, Chile, New Zealand, South Korea, and Thailand) spanning two decades (2000 to 2019), the research provided clear evidence of this protective effect.
Key Findings on Mental Health
The study found that locally accessible green space was associated with a 7% reduction in hospital admissions for all-cause mental disorders. The protective effects were even stronger for specific conditions:
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Substance Use Disorders: 9% reduction in hospital admissions.
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Psychotic Disorders: 7% reduction in hospital admissions.
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Dementia: 6% reduction in hospital admissions.
The protective effect on a person’s mental health was found to increase with greater exposure to greenness, with no clear threshold identified. The overall protective associations were strongest in urban areas, where it is estimated that 7,712 hospital admissions for mental disorders annually could potentially be prevented through greater exposure to greenness.
The analysis did note variations across countries and disorders. Protective associations were consistently observed across most disorders in Brazil, Chile, and Thailand, while in Australia and Canada, greenness was associated with modestly increased risks for some disorders.
Global Health Challenge
Mental well-being is a critical global challenge. According to researchers, 1.1 billion people had mental disorders in 2021, contributing to 14% of the global disease burden, along with significant associated economic and societal costs.
This study is particularly important because it is the largest of its kind to analyze a comprehensive range of mental disorders and specific categories, including psychotic disorders, mood disorders, behavioral disorders, and anxiety. Researchers measured greenness using the Normalized Difference Vegetation Index (NDVI), a reliable, satellite-derived metric for assessing vegetation levels. They controlled for numerous factors, including population levels, air pollutants, weather conditions, socioeconomic indicators, and seasonality.
The mental health benefits of green space may also bring broader economic advantages, including reduced healthcare costs, decreased strain on health systems, improved workplace productivity, and enhanced community well-being. This evidence strongly suggests that future urban design and health policy should prioritize integrating natural spaces to better protect public mental health.
