Sebastian Junger, former war reporter and author of "Tribe- on homecoming and belonging" talks about the importance of belonging to a community or "tribe" for mental well being.
"As wealth goes up in a society, as modernity goes up in a society – the suicide rate goes up. The depression rate goes up. Schizophrenia goes up in urban environments. We are evolved to live in groups of 30-40 people in a harsh environment, totally inter-reliant on one another for survival. This creates a huge amount of equality and loyalty within a group. That's what we are designed for genetically.
Modern society allows for the individual to be independent from the group, which is in some sense a great liberation, in other ways it can lead to a profound alienation and depression."