Madness in the City By James Reed
I think it was Madison Grant (1865-1937), who saw Nordic (Northern Europeans) facing decline through life in the big cities: https://www.amazon.com/Passing-Great-Race-Madison-Grant/dp/1471022935. City life while giving some benefits, ultimately led to cultural degeneracy.
Research conducted by King’s College London and Duke University has found that city life may be unhealthy for all people, with the greater the degree of urbanicity, the greater the risk of mental problems: http://www.dailymail.co.uk/health/article-4531024/Do-live-city-likely-hear-voices.html. There were 40 percent more episodes of psychosis in urban areas compared to rural areas, and 62 percent of 18-year-olds, who lived in high crime areas, had mental health issues, including hearing voices and paranoia. Thirty-four percent reported psychotic symptoms between the age of 12 and 18.
City living can lead to increased stress, which in turn effects the biochemistry of the brain, in particular, producing excess dopamine, a neurotransmitter. The lack of trust and the low levels of social capital, along with high levels of threat and potential violence, also impacted upon the prevalence of psychosis and paranoia.
Cities have become monuments to the decay and death of Western civilisation: https://www.amazon.com/Geography-Nowhere-Americas-Man-Made-Landscape/dp/0671888250.