Immigrant Mania

From The Hypomanic Edge:
"A small empirical literature suggests that there are elevated rates of manic-depressive disorder among immigrants, regardless of what country they are moving from or to. America, a nation of immigrants, has higher rates of mania than every other country studied (with the possible exception of New Zealand, which topped the United States in one study). In fact, the top three countries with the most manics -- America, New Zealand, and Canada -- are all nations of immigrants. Asian countries such as Taiwan and South Korea, which have absorbed very few immigrants, have the lowest rates of bipolar disorder."
Interesting. And, while that may not sound altogether positive, percentage of manics correlates with percentage of hypomanics (a milder form of mania, not necessarily accompanied by depression), and hypomania may in fact be a positive attribute when it comes to entrepreneurial and other kinds of success. I've only read to page 12, though.