U.S. has the highest rate of mental illness

"Mental illnesses including anxiety disorders and depression are common and undertreated in many countries, both developed and developing, with the highest rate found in the United States, according to a study of 14 countries.
Based on face-to-face diagnostic surveys in the homes of 60,463 adults, the study found that mental ailments affect more than 10 percent of people queried in more than half the countries surveyed.Nigerians appeared to have the lowest prevalence of mental illness, 4.7 percent, but the researchers think the actual number is probably much higher as residents of the violence-prone West African nation may be hesitant to confide in strangers. The highest rate was found in the United States, with 26.4 percent."