Cities are increasingly full of people. The urban population doubled from 25% in 1950 to 56.2% in 2020. What's more, it is expected to continue increasing to 58% in the next 50 years.
At the same time, mental disorders have increased from 654.8 million cases in 1990 to 970.1 million in 2019, which corresponds to an increase of 48.1%. And the suspicion that it may be related has led to increased research on the relationship between urbanization and mental health.
Studies indicate that living in the city is associated with greater activity of the amygdala, an essential part of the response to stress and anxiety. In fact, the prevalence rate of many mental health problems is higher in cities than in rural areas: approximately 40% higher risk of depression, 20% higher risk of anxiety, and double the risk of schizophrenia.
In the past, cities were planned based on commercial and productive interests, without taking into account the well-being of their inhabitants. But currently a paradigm shift is necessary, especially after the major global crises generated by climate change and the Covid-19 pandemic. There are various factors of life in cities that can act as stressors: overcrowding, noise, pollution, and, of course, the urban design itself.
If when looking around us we see an excess of repetitive and geometric patterns such as those of buildings, this can cause visual stress. In fact, a predictor of perceived urban stress is the number of isovistic vertices, that is, the number of vertices visible to an individual located in a given location.
On the contrary, the natural environment seems to have greater fractal complexity, which implies a lower number of ocular fixations and, therefore, less effort in the processing of visual information.
However, not everything that the city gives us is negative for our psyche. Good accessibility to public transport, coupled with a dense (rather than sprawling) urban structure, increases opportunities for an active social life and contributes to reducing the risk of depression, especially for older people and people with special needs.
Urban environmental conditions, such as lack of natural light or little contact with nature, can affect mood and emotions. The benefits of incorporating green spaces into urban environments have been repeatedly demonstrated. These benefits are mainly related to the possibility of developing physical activities in green spaces. What's more, mere exposure to natural elements, such as the sky, trees, water, natural light or breeze reduce the perception of stress.
What dose of nature do we need exactly? Surprisingly, just five minutes of exposure to green areas produces significant recovery from stress.
Architectural solutions that alleviate urban stress are considered part of the sustainable strategy to plan human-friendly cities, which is in line with Sustainable Development Goal 11 that the World Health Organization has set for 2030. In specifically, with goal 1.3 (inclusive and sustainable urbanization), and goal 11.7 (provide access to public, safe and inclusive green spaces).
Investigating the impact that different factors of the built environment have on the stress response of people, particularly the most vulnerable, is essential to define healthy urbanization criteria. Psychology and neuroscience have the appropriate tools to evaluate the perception of the environment through the behavioral responses of individuals, eye movement tracking techniques, physiological responses such as heart rate or blood pressure and even activity. brain physiology measured with techniques such as magnetic resonance imaging.
There are initiatives such as that of the 7 Senses Foundation, in Australia, which works to develop healthier neighborhoods by demanding the multidisciplinary design of public spaces.
What seems indisputable is that urban stress is a multifactorial problem that can be prevented with collaboration between those responsible for urban planning and psychology and neuroscience researchers to design cities that promote mental health through protective elements.
This article was originally published on The Conversation. Eva Mª Rosa Martínez is a professor at the Department of Basic Psychology at the University of Valencia. Carmen Berenguer is a professor in the Department of Developmental and Educational Psychology at the University of Valencia.
