[t0dd]

Some recent research suggests the primary factor is "residential instability":

"Put another way, the very traits associated with the West (and romanticized in American culture)—individualism and independence, stoicism and solitude—may also have deeply negative implications for its people."

http://www.rwjf.org/en/about-rwjf/newsroom/newsroom-content/...

[prawn]

Thanks for the link.

"They also guessed that the West's low population density might play a role in its high suicide rates, but the findings did not bear that out."

For others who don't read the article, residential instability is their suggestion leading to lessened social integration.