Prevalence

Mental disorders have been found to be relatively common, with more than one in three people in most countries reporting sufficient criteria for at least one diagnosis at some point in their life up to the time they were assessed. A new WHO global survey currently underway indicates that anxiety disorders are the most common in all but 1 country, followed by mood disorders in all but 2 countries, while substance disorders and impulse-control disorders were consistently less prevalent. Rates varied by region. Such statistics are widely believed to be underestimates, due to poor diagnosis (especially in countries without affordable access to mental health services) and low reporting rates, in part because of the predominant use of self-report data rather than semi-structured instruments.[citation needed] Actual lifetime prevalence rates for mental disorders are estimated to be between 65% and 85%.[citation needed]

A review of anxiety disorder surveys in different countries found average lifetime prevalence estimates of 16.6%, with women having higher rates on average. A review of mood disorder surveys in different countries found lifetime rates of 6.7% for major depressive disorder (higher in some studies, and in women) and 0.8% for bipolar 1 disorder.

The updated US National Co morbidity Survey (NCS) reported that nearly half of Americans (46.4%) meet criteria at some point in their life for either an anxiety disorder (28.8%), mood disorder (20.8%), impulse-control disorder (24.8%) or substance use disorder (14.6%).