Background
The mental disorders included in the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 were depressive disorders, anxiety disorders, bipolar disorder, schizophrenia, autism spectrum disorders, conduct disorder, attention deficit hyperactivity disorder , eating disorders, idiopathic intellectual developmental disabilities and a residual category of other mental disorders.
We aimed to measure global, regional and national prevalence, disability-adjusted life years (DALYS), years lived with disability (YLD) and years of life lost (YLL) for mental disorders from 1990 to 2019.
* Disability-adjusted life years (DALYs)
Mental disorders are increasingly recognized as leading causes of the burden of disease. The Lancet Commission on Global Mental Health and Sustainable Development emphasized mental health as a fundamental human right essential for the development of all countries. The Commission called for more investment in mental health services as part of universal health coverage and better integration of these services into the overall response to other health priorities.
To meet the mental health needs of individual countries in a way that prioritizes the transformation of health systems, a deep understanding of the scale of the impact of these disorders is essential, including their distribution in the population, the health burden imposed and its broader health consequences.
Methods
In this study, we assessed GBD 2019 prevalence and burden estimates for 12 mental disorders, men and women, 23 age groups, 204 countries and territories, between 1990 and 2019. DALYs were estimated as the sum of YLD and YLL up to premature mortality. We systematically reviewed PsycINFO, Embase, PubMed, and Global Health Data Exchange to obtain data on prevalence, incidence, remission, duration, severity, and excess mortality for each mental disorder. These data 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. The cause-of-death set modeling strategy was used to estimate the mortality rate by age, sex, year, and location.
Mortality rates were multiplied by the years of life expected to remain at the time of 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 in GBD 2019.
Results
Between 1990 and 2019, the global number of DALYs due to mental disorders increased from 80.8 million (95% uncertainty interval [UI] 59.5–105.9) to 125.3 million (93.0–163. 2), and the proportion of overall DALYs attributed to mental disorders increased from 3.1% (95% UI 2.4–3.9) to 4.9% (3.9–6.1).
Age-standardized DALY rates remained largely constant between 1990 (1581·2 DALYs [1170·9–2061·4] per 100,000 people) and 2019 (1566·2 DALYs [1160·1–2042·8 ] per 100,000 people).
YLDs contributed to the majority of the burden of mental disorders, with 125.3 million YLDs (95% UI 93.0–163.2; 14.6% [12.2–16.8] global YLDs) in 2019 attributable to mental disorders. Eating disorders accounted for 17,361·5 YLL (95% UI 15,518·5–21,459·8).
Globally, the age -standardized DALY rate for mental disorders was 1426·5 (95% UI 1056·4–1869·5) per 100 000 population among men and 1703·3 (1261·5–2237· 8) per 100,000 inhabitants among women. Age-standardized DALY rates were highest in Australasia, tropical Latin America, and high-income North America.
DALYs by global mental disorder, sex and age, 2019.
DALYs = disability-adjusted life years.
Interpretation
GBD 2019 showed that mental disorders remained among the top ten causes of burden worldwide, with no evidence of a global reduction in burden since 1990.
The estimated YLLs for mental disorders were extremely low and do not reflect premature mortality in people with mental disorders. Research is recommended to establish causal pathways between mental disorders and other fatal health outcomes so that this can be addressed within the GBD study.
To reduce the burden of mental disorders, coordinated implementation of effective prevention and treatment programs by governments and the global health community is imperative.
Discussion
In 2019, we observed similar disparities in the global distribution and burden of mental disorders as in 1990. Depressive and anxiety disorders remained among the leading causes of burden worldwide (ranked 13th and 24th among leading causes of DALYs, respectively) with prevalence estimates and disability weights comparatively higher than many other diseases.
Schizophrenia affected a smaller proportion of the world’s population than depressive and anxiety disorders , but the disability burden for an acute state of psychosis was the highest estimated in the entire GBD study. The persistently high prevalence of these disorders, in addition to bipolar disorder and eating disorders , is especially concerning, because they not only impair health in and of themselves, but also increase the risk of other health outcomes.
- We did not find marked variation in burden by sex for bipolar disorder and schizophrenia.
- The burden of depressive disorders, anxiety disorders, and eating disorders was higher in women than in men.
- The burden of autism spectrum disorders and ADHD was higher in men than in women.
In 2019, 80.6% of the burden of mental disorders occurred among people of working age (16-65 years). About 9.2% of the remaining burden occurred in people under 16 years of age. In 2019, 23.2% of the world’s children and adolescents were in sub-Saharan Africa, where mental disorders in these age groups pose considerable challenges to economies that already have limited resources dedicated to mental health. at a stage of development when implementation of prevention and early intervention strategies for mental disorders are crucial.
Overall, DALY rates for mental disorders were high in many high-income countries and were lower in parts of sub-Saharan Africa and Asia, where epidemiological data coverage was lower and therefore there is more uncertainty in around the estimates. Disorder-specific trends were also identified. For example, DALYs for depressive and anxiety disorders were high in countries with high rates of childhood sexual abuse, intimate partner violence, and conflict and war.
Age-standardized DALY rates for mental disorders remained fairly constant between 1990 and 2019, but the total number of DALYs increased by 55.1%. This growth is expected to continue due to population growth and highlights the need for health systems, especially those in low- and middle-income countries, to provide the necessary treatment and care for this growing population.
There are effective intervention packages for mental disorders. These interventions have the potential to reduce the burden due to mental disorders by decreasing the severity of symptoms, increasing remission, or reducing the risk of mortality. However, globally, there is a substantial shortage in access to these services and in the resources allocated for their expansion, as well as various barriers to care, such as the perceived need for care and the stigma surrounding health problems. mental.
In high-income countries where increases in uptake of treatment for mental disorders have been observed since 1990, treatment still does not meet adequate minimum standards or those in the population who need it most. To reduce the burden of mental disorders, we need to expand the delivery of effective prevention and treatment programs with established efficacy.26 to cover a larger portion of the population for the time needed.
The emergence of the COVID-19 pandemic in 2020 has created an environment in which many determinants of poor mental health outcomes have been exacerbated.
Epidemiological research suggests that the direct psychological effects of the pandemic and the long-term impacts on the economic and social circumstances of a population could increase the prevalence of common mental disorders. Efforts to establish the data set and methodology from which the impact of the COVID-19 pandemic on the burden of mental disorders within the GBD study can be quantified have been summarized elsewhere.
Our findings demonstrated that mental disorders already imposed a substantial burden before the COVID-19 pandemic. While it is important to consider the impact of COVID-19 on mental health, the existing unmet mental health needs of the population must also be considered as we focus on recovery from this pandemic. Our GBD 2019 results serve as a stark reminder for countries to re-evaluate their mental health service response more broadly.
The GBD 2019 findings emphasize the large proportion of the global disease burden attributable to mental disorders and the global disparities in that burden.
Furthermore, there was no evidence of an overall reduction in burden since 1990, despite evidence-based interventions that can reduce burden based on age, sex, and geographic location.
The continued impact of the COVID-19 pandemic is likely to increase the global burden of mental disorders. A coordinated response from governments and the global health community is urgently needed to address the current and future gap in mental health treatment.
Research in context
Added value of this study
Using the most up-to-date information on the prevalence and burden of mental disorders in the global population, excluding substance use disorders and suicide, for 2019, we see similar disparities in the burden of mental disorders as in 1990.
Mental disorders remained among the leading causes of burden globally.
Disability-adjusted life years ( DALYs) for mental disorders were evident across all age groups, emerging before age 5 in people with idiopathic intellectual disability and autism spectrum disorders, and continuing to be evident at older ages in people with depressive disorders, anxiety disorders and schizophrenia. We identify priority areas for improving epidemiological data and methodology for estimating the burden of mental disorders, and provide recommendations on how to address these areas.
Implications of all available evidence
GBD 2019 confirmed that a large proportion of the world’s disease burden is attributable to mental disorders and found no evidence of a global reduction in that burden since 1990, despite research showing that interventions can achieve a reduction in the burden. burden.
Our findings highlighted the limitations of measures to estimate years of life lost to determine the effects of mental disorders on premature mortality. Research is needed to improve these measures to provide a more accurate picture of the true burden due to mental disorders.
Funding: Bill & Melinda Gates Foundation, National Health and Medical Research Council of Australia, Queensland Department of Health, Australia.
