Study Reveals Influence of Urban Environment on Mental Health

More than 50% of the world population lives in urban areas, and by 2050, two-thirds will live in cities. Urban-living individuals are exposed to numerous environmental factors that may combine and interact to influence mental health. While individual factors of urban environment have been investigated in isolation, no attempt has been made so far to model how complex, real-life exposure to living in the city relates to brain and mental health, and how this is influenced by genetics.

Using data of 156,075 participants from the UK Biobank, the team identified urban living environmental profiles and related them to psychiatric symptoms. They also identified regional brain areas that mediated the effect of the different environmental profiles on psychiatric symptoms.

The researchers found an environmental profile of social deprivation, air pollution, street network and urban land use density that was related to higher symptoms of depression, which were mediated by brain volume differences. These brain volume differences were found in regions known to process reward. The degree of brain volume change depended on variations in genes related to stress response. Protective factors such as greenness and generous destination accessibility were related with fewer anxiety symptoms, mediated by brain regions necessary for emotion regulation. The third urban environmental profile was related to an emotional instability symptom group.

Prof. Gunter Schumann, Head of the Centre for Population Neurosciences and Stratified Medicine (PONS) at Charité – Universitätsmedizin Berlin and Fudan University Shanghai, explains: “We aim to understand what combinations of environmental factors are most relevant for psychiatric symptoms. By providing evidence for comprehensive urban environmental profiles that affect distinct groups of psychiatric symptoms and are mediated by different brain mechanisms, our results characterised biological mechanisms underlying complex, real-life environmental adversity.”

This study is the first attempt to model how living in complex urban environments relates to brain and mental health and provides important insights into the relationships between urban environments and psychiatric symptoms. The findings have important implications for urban planners, city policymakers, and mental health professionals. The quantification of the contribution of each environmental factor to brain and psychiatric symptoms and their interplay in an urban living environment can aid in targeting and prioritising future public health interventions.