“Depression and Other Common Mental Disorders: Global Health Estimates.” By the World Health Organization; published 2017.

• OVERVIEW: Reliable, up-to-date estimates of the proportion of a general population affected by different diseases or health conditions is a key ingredient of effective health policy, planning and evaluation. This booklet provides latest available estimates of the prevalence of depression and other common mental disorders at the global and regional level, together with data concerning the consequences of these disorders in terms of lost health. Globally, the total number of people with depression was estimated to exceed 300 million in 2015. Nearly that number again suffers from a range of anxiety disorders. Since many people experience both conditions simultaneously (comorbidity), it is inappropriate to simply add these two figures together to arrive at a total for common mental disorders. The consequences of these disorders in terms of lost health are huge. Depression is ranked by WHO as the single largest contributor to global disability (7.5% of all years lived with disability in 2015); anxiety disorders are ranked 6th (3.4%). Depression is also the major contributor to suicide deaths, which number close to 800 000 per year.

“The Global Burden of Disease.” By the World Health Organization; published 2004.

• OVERVIEW: A consistent and comparative description of the burden of diseases and injuries, and risk factors that cause them, is an important input to health decision-making and planning processes. Information that is available on mortality and health in populations in all regions of the world is fragmentary and sometimes inconsistent. Thus, a framework for integrating, validating, analysing and disseminating such information is needed to assess the comparative importance of diseases and injuries in causing premature death, loss of health and disability in different populations.

“Lifetime Prevalence and Age-of-Onset Distributions of DSM-IV Disorders in the National Comorbidity Survey Replication.” By Ronald C. Kessler, Patricia Berglund, Olga Demler, Robert Jin, Kathleen R. Merikangas, and Ellen E. Walters; published 2005 in the Archives of General Psychiatry.

• ABRIDGED ABSTRACT: Context: Little is known about lifetime prevalence or age of onset of DSM-IV disorders. Objective: To estimate lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the recently completed National Comorbidity Survey Replication. Conclusions: About half of Americans will meet the criteria for a DSM-IV disorder sometime in their life, with first onset usually in childhood or adolescence. Interventions aimed at prevention or early treatment need to focus on youth.

“Mental Health By the Numbers.” By the National Alliance on Mental Illness; updated 2021.

• OVERVIEW: Millions of people in the U.S. are affected by mental illness each year. It’s important to measure how common mental illness is, so we can understand its physical, social and financial impact — and so we can show that no one is alone. These numbers are also powerful tools for raising public awareness, stigma-busting and advocating for better health care.

“Prevalence, Severity, and Comorbidity of Twelve-month DSM-IV Disorders in the National Comorbidity Survey Replication (NCS-R).” By Ronald C. Kessler, Wai Tat Chiu, Olga Demler, and Ellen E. Walters; published 2010 in the Archives of General Psychiatry.

• ABRIDGED ABSTRACT: Context: Little is known about the general population prevalence or severity of DSM-IV mental disorders. Objective: To estimate 12-month prevalence, severity, and comorbidity of DSM-IV anxiety, mood, impulse-control, and substance disorders in the recently completed US National Comorbidity Survey Replication (NCS-R). Conclusions: Although mental disorders are widespread, serious cases are concentrated among a relatively small proportion of cases with high comorbidity.