Living in a dense urban environment may be making you crazy. Literally. A new article in Nature hypothesizes that there may be a strong link between the rapid urbanization of the world’s population and the increase in mental health issues, such as schizophrenia. While there have been no large-scale studies, more localized studies suggest that prolonged exposure to highly stimulating urban environments locks the brain in a kind of permanent stress response that can lead to further mental complications. To find out more, the Lieber Institute for Brain Development in Baltimore, Maryland, is planning a massive, long-term study in China, where urbanization rates are highest.