Spending time in green spaces like parks, gardens, or forests may do more than just lift your mood—it could actually protect your mental health.
A new study, published in The BMJ’s climate issue, shows that living in greener areas is linked to fewer hospital visits for mental health problems.
This connection was seen across seven countries over a 20-year period, making it one of the largest studies of its kind.
Mental health is a growing issue worldwide. In 2021, about 1.1 billion people were living with mental disorders. These conditions now make up 14% of the world’s total disease burden and lead to huge costs for healthcare systems, families, and societies. Finding new and effective ways to prevent mental illness is a top priority for health experts.
One promising idea is increasing access to greenery. Some earlier studies suggested that being around nature could help reduce stress and improve mental well-being, but many of those studies only looked at one country or short time periods. This new study wanted to explore the relationship on a global scale.
Researchers looked at data from over 11 million hospital admissions for mental disorders between 2000 and 2019. These admissions came from more than 6,800 locations in Australia, Brazil, Canada, Chile, New Zealand, South Korea, and Thailand.
The study covered all mental disorders, as well as specific conditions like psychosis, substance use problems, mood disorders, anxiety, dementia, and behavioral disorders.
To measure the amount of greenery, researchers used satellite images to calculate something called the NDVI (Normalized Difference Vegetation Index), which shows how much plant life is in an area. They also considered other factors like population size, air pollution, temperature, income levels, and seasonal changes.
The findings showed that living in greener areas was linked to a 7% lower risk of going to the hospital for a mental health condition. The effect was even stronger for certain disorders—hospital visits were reduced by 9% for substance use disorders, 7% for psychotic disorders, and 6% for dementia.
Interestingly, people living in cities seemed to benefit the most from greener surroundings. In these urban areas, the researchers estimated that around 7,700 hospital admissions for mental disorders could be prevented each year by simply increasing exposure to greenery.
Seasonal changes also played a role—weather and climate affected how people used green spaces and how helpful those spaces were.
There were differences between countries too. In Brazil, Chile, and Thailand, the benefits of greenery were strong and consistent.
But in Australia and Canada, some links between greenery and better mental health were weaker or even showed slightly higher risks in greener areas. This suggests that local context—such as how green spaces are designed, maintained, and used—matters a lot.
The researchers also estimated that a 10% increase in greenery in urban areas could lead to fewer hospital admissions, ranging from one less per 100,000 people in South Korea to nearly 1,000 fewer per 100,000 in New Zealand.
While this study can’t prove that greenery directly causes better mental health, the strong patterns suggest a real connection. The researchers also admit that the study only looked at hospital-level care, so it doesn’t reflect all mental health issues in the population.
Still, the findings support the idea that making cities greener could be a powerful way to improve public mental health. Better mental health also means reduced healthcare costs, improved productivity, and stronger communities.
The researchers recommend future studies to look at different types of green spaces, such as parks or forests, and how accessible and high-quality they are.
In the end, this global study sends a clear message: adding more greenery to our neighborhoods isn’t just good for the environment—it could also be a smart and natural way to take care of our mental health.
If you care about mental health, please read studies about cannabis use disorder linked to increased risk of mental diseases and some mental health drugs can cause rapid weight gain.
For more health information, please read studies that one sleepless night can reverse depression for days and scientists find better treatment for older adults with depression.
The study is published in The BMJ.
Copyright © 2025 Knowridge Science Report. All rights reserved.
