Income divide as cause of social ills

The Globe today had an interview with Kate Pickett and Richard Wilkinson, authors of "The Spirit Level." The book compiles statistical evidence that levels of various social ills: "drug use, obesity, violence, mental illness, teenage pregnancy, illiteracy" are significantly higher in countries in which there is a wide gap between rich and poor.  I think the underlying causal factor that they may be pointing to that affects everyone in the society in which there is such a large gap is the way in which people's identities, regardless of where they are, become strongly associated with income.

It's Money that Matters

Link to Amazon reviews of the book: The Spirit Level