*** Accepted for publication at The Lancet Psychiatry ***
In this study, we assessed prevalence and burden estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019) for 12 mental disorders, males and females, 23 age groups, 204 countries and territories, between 1990 and 2019. The mental disorders included in GBD 2019 were depressive disorders, anxiety disorders, bipolar disorder, schizophrenia, autism spectrum disorders, conduct disorder, attention-deficit hyperactivity disorder, eating disorders, idiopathic developmental intellectual disability, and a residual category of other mental disorders.
Disability-adjusted life-years (DALYs) were estimated as the sum of years lived with disability (YLDs) and years of life lost to premature mortality (YLLs). Systematic reviews of the literature compiled data on the prevalence, incidence, remission, duration, severity, and excess-mortality imposed by each disorder. These informed a Bayesian meta-regression analysis to estimate prevalence by disorder, age, sex, year, and location. Prevalence was multiplied by corresponding disability weights to estimate YLDs. Cause-specific deaths were compiled from mortality surveillance databases. A Cause of Death Ensemble modelling strategy estimated deaths by age, sex, year, and location. These were multiplied by the years of life expected to be remaining at death based on a normative life expectancy to estimate YLLs. Deaths and YLLs could only be calculated for anorexia nervosa and bulimia nervosa, as these were the only mental disorders identified as underlying causes of death. These are not reflective of all premature mortality in individuals with mental disorders where the direct cause of death is another disease or injury.
From 1990 to 2019, the global number of DALYs due to mental disorders increased from 80·8 million to 125·3 million, and the proportion contributed by mental disorders increased from 3·1% (95% uncertainty interval 2·4–3·9) to 4·9% (3·9–6·1). Age-standardised DALY rates remained largely consistent between 1990 (1581·2 DALYs [1170·9–2061·4] per 100,000 population) and 2019 (1566·2 DALYs [1160·1–2042·8] per 100,000 population). YLDs contributed to almost all of the mental disorder burden, accounting for 125·3 million (93·0–163·2) YLDs or 14·6% (12·2–16·8) of global YLDs in 2019. Eating disorders accounted for 17 361·5 YLLs (15 518·5–21 459·8). Globally, males were responsible for 1426.5 (1056.4-1869.5) and females for 1703.3 (1261.5 - 2237.8) age standardized DALYs per 100,000 population for mental disorders. These DALYs were present across all age groups, emerging prior to 5 years with idiopathic intellectual disability and autism spectrum disorders, and continuing into older ages with depressive disorders, anxiety disorders, and schizophrenia. Although the relative contribution of each disorder changed with age and sex, overall DALYs increased steadily during childhood and adolescence, peaked between 25 and 34 years, and decreased steadily into the older ages. Age-standardised DALY rates were highest in Australasia, Tropical Latin America, and high-income North America.
GBD 2019 continued to emphasise the large proportion of the world’s burden attributable to mental disorders and the disparities in that burden. Mental disorders remained among the top ten leading causes of burden worldwide, with no evidence of sufficient global reduction in the burden. To reduce the burden of mental disorders, a coordinated response by governments and the global health community is imperative. We need to expand the delivery of effective prevention and treatment programmes with established efficacy to cover more of the population for the necessary duration. This study provided a detailed analysis of mental disorder burden but did not incorporate substance use disorders or suicide categorised separately within the GBD cause hierarchy. We also acknowledge that the estimated YLLs for mental disorders were extremely low, and not reflective of premature mortality in individuals with mental disorders. Further work to establish causal pathways between mental disorders and other fatal health outcomes is recommended so that this may be addressed within the GBD study.
GBD 2019 Mental Disorders Collaborators. Global, regional, and national burden of 12 mental disorders in 204 countries and territories, 1990–2019: a systematic analysis from the Global Burden of Disease Study 2019. The Lancet Psychiatry (In Press). Pre-print available at: https://www.healthdata.org/research-article/global-regional-and-national...