A lot of the interesting issues and dynamics within a city occur over things such as socio-economic issues or ethnic issues. But they require a much more elaborate model of human behavior. ↗
Physiology and psychology cover, between them, the field of vital phenomena; they deal with the facts of life at large, and in particular with the facts of human life. ↗
That's the thing about depression: A human being can survive almost anything, as long as she sees the end in sight. But depression is so insidious, and it compounds daily, that it's impossible to ever see the end. The fog is like a cage without a key. ↗