"The brains of people living in cities operate differently from those in rural areas, according to a brain-scanning study. Scientists found that two regions, involved in the regulation of emotion and anxiety, become overactive in city-dwellers when they are stressed and argue that the differences could account for the increased rates of mental health problems seen in urban areas.
Previous research has shown that people living in cities have a 21% increased risk of anxiety disorders and a 39% increased risk of mood disorders. In addition, the incidence of schizophrenia is twice as high in those born and brought up in cities.
Another region called the cingulate cortex was overactive in participants who were born in cities. "We know [the cingulate cortex] is important for controlling emotion and dealing with environmental adversity."" (via Guardian)
It is not really surprising that if you put too many people in one place, they will suffer from some effects like anxiety - this now is another scientific hint towards that. Another is that cities lack green plants, vital for human health.
Es ist ja keine große Überraschung daß Menschen psychische Probleme bekommen wenn sie sich zu dicht auf der Pelle hocken, wie in Großstädten. Aber jetzt gibt es dazu noch eine weitere Studie. Frühere Studien zeigten daß es derartige Probleme gibt und andere zeigen daß das Fehlen von Grünpflanzen (oder Natur im Allgemeinen) auch psychische Probleme auslöst.