A major new international study has found that living near more green spaces can reduce the risk of ending up in hospital for mental health problems — especially for city dwellers.
Researchers looked at a staggering 11.4 million mental health hospital admissions between 2000 and 2019 across seven countries: Australia, Brazil, Chile, New Zealand, Thailand, South Korea, and Canada.
They discovered that higher levels of greenery, measured by something called the normalized difference vegetation index (NDVI), were linked to a 7% drop in all mental health hospitalizations. The biggest benefits were seen for conditions like substance abuse, psychotic disorders, dementia, and anxiety.
In urban areas, the effect was even stronger. More green space meant a 13% reduction in mental health admissions — which could stop nearly 8,000 hospital stays every year.
But the impact wasn’t the same everywhere. Thailand showed the biggest drop in risk, while Australia saw the smallest.
The study also estimated that just a 10% boost in greenness could prevent up to 1,000 mental health hospital admissions per 100,000 people in some countries.
The researchers say increasing green spaces isn’t just good for the mind, it could save money on healthcare and improve community wellbeing too.
They do warn, though, that the study only looked at serious cases needing hospital care, and that green space quality — like safety or biodiversity — wasn’t measured.
Still, the message is clear: more parks and trees could be a powerful weapon in the fight for better mental health.
Source: Greenness and hospital admissions for cause specific mental disorders: multicountry time series study BMJ 2025;391:e084618