Implementing green corridors across Barcelona could reduce annual use of antidepressants

A health impact assessment conducted by the Barcelona Institute for Global Health (ISGlobal) concluded that the implementation of green corridors throughout the city of Barcelona would result in a “significant reduction” in the incidence of mental disorders in the adult population as well as in the associated direct and indirect costs. on the aforementioned cases. The study has been published in the journal international environment.

It is estimated that mental health disorders are responsible for more than 30% of the global burden of disease. Scientific evidence shows that green spaces benefit public health – and mental health in particular – through various mechanisms, for example by reducing exposure to air, noise and heat pollution; By reducing stress and facilitating restorative processes in the body; and by encouraging physical activity and social interaction.

In this study, the research team set out to assess the mental health effects of the strategy developed by the city to, among other things, reallocate more public spaces to greenery. This plan, known as the Green Hubs (Eixos Verds in Catalan), forms part of the Barcelona Superblock project. It is currently being implemented primarily in the city centre, although it envisages eventually converting one in three streets into a green corridor.

The researchers obtained data from a previous study that determined the amount of land designated for green space and the degree of green space across the city in 2015. They then calculated the increase in green space that the implementation of the green hubs plan would produce across the entire city. .

Data on the mental health of the population was obtained from the Barcelona Health Survey (2016-2017). By applying calculations from previous research on the relationship between residential green space and mental health, the researchers were able to estimate how a planned increase in green space under the Green Hubs Scheme would affect several mental health outcomes across the population.

The results showed that in the case of full implementation of the green hubs plan, it will lead to an increase in green spaces at the city level by 5.67%, especially in residential areas. This increase in vegetation, in turn, would result in the prevention of 14% of cases of perceived mental ill health, 13% of visits to mental health professionals and cases of antidepressant use, and 8% of cases of use of sedatives/sedatives each year.

The researchers further concluded that the mental health benefits for the population would translate into an annual saving of €45 million in direct and indirect mental health costs.

ISGlobal researcher Natalie Müller, author of the latest study, commented: “Barcelona has a problem that needs an urgent solution.” “Only 11% of the city is currently set aside for green space – and this includes Collserola Park, which accounts for 60% of the city’s green space. In the Eixample district, for example, only 6.5% of the land area is set aside for green space.

However, in order to comply with the WHO recommendation of at least 500m2 Green space 300 meters from each house, and we calculate that this number should reach 25% of the land area.

“Only 20% of Barcelona’s population currently lives in a place that meets the World Health Organization’s recommendation for green spaces. And at a European level, only 40% of urban residents have the recommended access to green spaces, which shows that we still have a lot of work to do.” to do in terms of greening our cities,” explained ISGlobal researcher Evelise Pereira, co-author of the study.

“This study helps demonstrate that greening is a relevant strategy for promoting health, especially mental health, in urban settings,” says co-author Diana Vidal-Yanez.

“Although our study assessed the potential impact of the Green Hubs plan, the findings do not apply exclusively to Barcelona,” commented Marc Nieuwenhojsen, Director of Urban Planning, Environment and Health Initiative at ISGlobal.

“Any measure in a city that increases the amount of green space near people’s homes should lead to improvements in the mental health burden among residents. However, for these benefits to be realized, it is essential that interventions be evenly distributed across the city accompanied by complementary policies. , such as high-quality public and active transport systems, low-emission zones, and anti-speculative and optimization policies.”