Preliminary results from the world's largest survey on mental health indicate that mental illness is widespread and undertreated.

9 to 17 percent of those interviewed had had some episode of mental illness in the last year.

"The level of role impairment we found to be associated with serious mental disorders was staggering."

About 26 percent of Americans were judged to have mental illness, compared with only 4 percent of the residents of Shanghai and 5 percent of Nigerians.

"It sounds like Nigeria is a paradise."