Background. This is the first study to examine variation across cohorts in lifetime risk of DSM-IV mental disorders in metropolitan China.

Method. Face-to-face household interviews of 2633 adults in Beijing and 2568 adults in Shanghai were conducted from November 2001 to February 2002 using a multi-stage household probability sampling method. The Chinese World Mental Health (WMH) Survey Initiative version of the WHO Composite International Diagnostic Interview (WMH-CIDI) was used for assessment.

Results. Lifetime prevalence of any disorder was 13·2%. Alcohol abuse (4·7%), major depressive disorder (3·5%), and specific phobia (2·6%) were the most common disorders. The median age of onset was later for mood (43 years) than anxiety (17 years) and substance use (25 years) disorders. Compared to observed lifetime prevalence, the projected lifetime risk as of age 75 years increased by 106% for major depressive disorder (7·2%), and was uniformly higher for all disorders. Relative odds of any lifetime disorder were 4·7 in the most recent cohorts (ages 18–34) compared to the eldest cohorts (ages [ges ]65).

Conclusions. The findings of this cross-sectional study tally with the view that rapid socioeconomic changes may bring about increasing incidence of mental disorders in China. However, prospective longitudinal studies are needed to confirm if the increase is real. Because of the huge size of the Chinese population, any increase in projected lifetime risk of mental disorders represents an enormous increase in the number of affected individuals.