Mao QS, Guo YX, Tian XL, Zhao HL, Kong YZ. Global burden of mental disorders in 204 countries and territories results from the Global Burden of Disease Study 2021. World J Psychiatry 2025; 15(8): 106887 [DOI: 10.5498/wjp.v15.i8.106887]
Corresponding Author of This Article
Yu-Zhe Kong, Xiangya School of Medicine, Central South University, No. 172 Tongzipo Road, Changsha 410013, Hunan Province, China. csuyuzhekong@foxmail.com
Research Domain of This Article
Health Policy & Services
Article-Type of This Article
Observational Study
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Qing-Song Mao, Hai-Long Zhao, Department of Hepatobiliary Pancreatic Surgery, Banan Hospital Affiliated of Chongqing Medical University, Chongqing 410132, China
Yu-Xin Guo, Xinxiang Medical University, Xinxiang 20000, Henan Province, China
Xin-Ling Tian, Yu-Zhe Kong, Xiangya School of Medicine, Central South University, Changsha 410013, Hunan Province, China
Co-corresponding authors: Hai-Long Zhao and Yu-Zhe Kong.
Author contributions: Mao QS contributed to formal analysis and writing the original draft; Guo YX contributed to data curation; Tian XL contributed to visualization; Zhao HL and Kong YZ edited the manuscript and made equal contributions as co-corresponding authors. All authors approved the final version to publish.
Institutional review board statement: This article is based on a secondary analysis of the Global Burden of Disease database. The Global Burden of Disease database does not contain individual-level data, thus allowing for relevant exemptions.
Informed consent statement: This study was conducted by using data from the Global Burden of Disease Study 2021. In this database, it didn’t contain individual level data. Thus, informed consent wasn’t needed.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Data sharing statement: Corresponding authors may provide data upon request.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Yu-Zhe Kong, Xiangya School of Medicine, Central South University, No. 172 Tongzipo Road, Changsha 410013, Hunan Province, China. csuyuzhekong@foxmail.com
Received: March 13, 2025 Revised: April 29, 2025 Accepted: June 17, 2025 Published online: August 19, 2025 Processing time: 150 Days and 18.6 Hours
Abstract
BACKGROUND
Mental disorders have become a major contributor to the Global Burden of Disease (GBD), a situation that has worsened with the onset of the coronavirus disease 2019 (COVID-19) pandemic. Updated data on their impact and a clear understanding of long-term trends are essential for global and national health authorities to implement effective prevention and intervention strategies for mental well-being.
AIM
To generate insights that will enhance global awareness of the burden of mental disorders and support the development of targeted, region-specific prevention and intervention strategies tailored to current global and local health challenges.
METHODS
We extracted data on incidence, disability-adjusted life years (DALYs), age-standardized incidence rate (ASIR), and age-standardized DALY rate (ASDR) for 12 categories of mental disorders from 1990 to 2021 across 204 countries and territories grouped into 21 regions. Trends in ASIR and ASDR were also analyzed during the COVID-19 period (2019-2021).
RESULTS
From 1990 to 2021, global ASIR rose by 15.23% (12.97% to 17.60%), while ASDR increased by 73.52% (70.24% to 76.71%). All 21 GBD regions saw a rise in cases and DALYs. In 2021, Central sub-Saharan Africa had the highest ASIR (8706.11), and East Asia reported the lowest (3340.99). Australasia recorded the highest ASDR (2787.87). On the national level, Greenland, Greece, United States, and Australia had the greatest ASDR values. During the pandemic years, ASIR and ASDR rose across all five socio-demographic index levels and GBD regions, with the exception of East Asia, where rates remained stable. Females experienced a higher ASDR than males in 2021. Major depressive disorder (557.87) and anxiety disorders (524.33) were the most burdensome among the 12 types, with depressive disorders ranking first in 13 out of the 21 regions.
CONCLUSION
The GBD study 2021 results highlight a continued and worsening global burden of mental disorders, further intensified by the COVID-19 crisis. This underscores the urgent need to reinforce mental health care systems. Special attention should be directed toward high-middle socio-demographic index areas and female populations. Expanding access to mental health services, enhancing public awareness, and delivering targeted interventions are essential to lessen the growing impact of mental disorders.
Core Tip: Mental disorders, one of the leading causes of the global health-related burden. Global Disease Burden Study 2021 showed that the burden of mental disorders was still on the rise gradually worldwide. The burden exacerbated by the emergence of the coronavirus disease 2019 pandemic. The mental disorders burden of high-middle socio-demographic index regions and females should be paid more attention.
Citation: Mao QS, Guo YX, Tian XL, Zhao HL, Kong YZ. Global burden of mental disorders in 204 countries and territories results from the Global Burden of Disease Study 2021. World J Psychiatry 2025; 15(8): 106887
Emerging from the inaugural Global Burden of Disease (GBD) analysis conducted in the 1990s, an expanding body of research has increasingly confirmed that neuropsychiatric disorders, including a broad range of psychiatric conditions, substance use disorders, and intentional self-injury, constitute a critical and escalating global public health concern[1]. These disorders not only carry substantial implications for individual health but also exert profound social and economic consequences at the population level. Over recent decades, their prominence in global morbidity and mortality rankings has steadily risen, placing them among the leading causes of disability worldwide. The emergence of the coronavirus disease 2019 (COVID-19) pandemic has further magnified these issues. It has exacerbated existing structural deficiencies within healthcare systems, widened preexisting sociodemographic disparities, and triggered widespread psychological distress. The pandemic’s sweeping and multifaceted societal disruptions, ranging from prolonged isolation and economic insecurity to increased exposure to trauma and loss, have created fertile conditions for the worsening of mental health outcomes across multiple demographic groups[2,3].
The GBD study, spearheaded by the Institute for Health Metrics and Evaluation, represents one of the most comprehensive and methodologically rigorous international efforts to monitor disease burden trends over time. This multinational epidemiological surveillance initiative systematically quantifies and compares the impact of various diseases, injuries, and risk factors across nations and regions. By producing standardized health metrics such as incidence, prevalence, mortality, and disability-adjusted life years (DALYs), the GBD study enables cross-national comparisons and generates vital data for informing health policy, guiding resource allocation, and shaping evidence-based intervention strategies[4]. Notably, the GBD’s longitudinal scope, spanning several decades, provides an invaluable framework for detecting secular trends, evaluating the outcomes of public health interventions, and anticipating future disease trajectories amid changing epidemiological landscapes.
In recent years, particularly among Asian populations, GBD surveillance data have highlighted a disturbing uptick in the incidence and burden of substance-related disorders, including alcohol dependence and illicit drug use, as well as rising rates of intentional self-harm. These conditions not only undermine the physical and mental well-being of affected individuals but also precipitate cascading societal effects. These include increased familial instability, reduced workforce participation, greater demand on social and healthcare services, and long-term economic ramifications[5,6]. Adolescents have emerged as a particularly vulnerable group in this context. Due to the developmental plasticity of the adolescent brain, ongoing identity formation, and heightened exposure to social stressors, young individuals are more susceptible to mental health deterioration and experimental substance use, especially during times of societal upheaval[7]. In this light, a detailed quantification of the mental health burden attributable to these factors is essential. Such data are crucial for designing responsive, age-appropriate, and culturally informed preventive and therapeutic strategies that are attuned to the evolving needs of diverse populations. However, despite the growing recognition of this issue, empirical research focused on the mental health consequences of the COVID-19 pandemic among Asian adolescents remains notably scarce, highlighting an urgent need for scholarly engagement and public health prioritization.
Therefore, the present study seeks to systematically examine the incidence, DALYs, and temporal trends of mental disorders across different countries and regions, spanning the period from 1990 to 2021 and the pandemic-impacted window from 2019 to 2021. Analyses will be stratified by gender to capture differential vulnerability patterns. Leveraging data from the 2021 iteration of the GBD study, this research aims to generate insights that will enhance global awareness of the burden of mental disorders and support the development of targeted, region-specific prevention and intervention strategies tailored to current global and local health challenges.
MATERIALS AND METHODS
Data source
This analysis utilized epidemiological data from the GBD 2021 repository (accessible viahttp://ghdx.healthdata.org/gbd-results-tool), which holistically evaluates 369 pathological conditions and 87 risk determinants across 204 nations from 1990-2021[8]. The computational framework for quantifying 12 neuropsychiatric conditions’ disease burdens follows established protocols detailed in prior methodological publications[9,10]. Mortality records for these psychiatric conditions were compiled through national civil registration systems, mortality surveillance networks, and postmortem interviews. These raw datasets underwent rigorous quality enhancement processes to rectify misclassification errors and spatial-temporal data discontinuities[11]. A Bayesian hierarchical modeling platform (cause of death ensemble model) subsequently generated stratified mortality estimates by geographic unit, temporal period, demographic cohort, and biological sex[10,12]. A comparative risk evaluation framework identified key environmental determinants, with particulate matter exposure being quantified through population-attributable fraction calculations. Air pollution-associated mortality and disability metrics were computed by applying these exposure-response coefficients to demographic-specific health outcome data[8].
The DALY metric integrates mortality-derived years of life lost and morbidity-related years lived with disability. Years of life lost computations multiplied age-stratified mortality counts by corresponding standard life expectancies, while years lived with disability estimations combined disorder prevalence rates with empirically validated disability weights[12]. National development status was categorized using the socio-demographic index (SDI), a composite measure (0-100 scale) incorporating educational attainment, economic productivity, and fertility patterns. Jurisdictions were subsequently grouped into five SDI quintiles for comparative analysis[12].
Definition
In this study, twelve categories of mental disorders were systematically identified and classified according to the diagnostic framework provided by the International Classification of Diseases, 10th revision. These classifications were applied consistently across all regions and time periods to ensure uniformity in diagnostic coding and cross-population comparability. Specifically, bipolar disorders were defined using International Classification of Diseases 10th revision codes ranging from F30 to F31.9, including the cyclothymic disorder code F34.0. Anxiety-related disorders encompassed a wider range, incorporating codes F40 through F44.9, along with childhood anxiety syndromes classified under F93 to F93.2. Eating disorders were delineated by the code range F50 to F50.9, while autism spectrum disorders were represented by F84 to F84.9. The diagnostic criteria for attention-deficit/hyperactivity disorder were covered under F90 to F90.9, and conduct disorders were captured within the F91 to F92.9 range.
Idiopathic developmental intellectual disability, representing a spectrum of cognitive impairments not attributable to known physiological causes, was assigned codes from F70 to F79.9. The category of other mental disorders was constructed to include a heterogeneous collection of neuropsychiatric conditions spanning multiple domains, such as organic mental disorders (F04-F06.1), affective disorders beyond bipolar and depressive categories (F34, F34.8-F39), sleep and somatoform disorders (F45-F49, G47-G47.29, G47.4-G47.9), personality disorders, and other specified and unspecified psychiatric conditions (F21-F24, F26-F29.9, F51-F52.9, F55-F69.0, F80-F83, F85-F89.0, F93.3-F99.0, R40-R40.4, R45-R46.89).
Schizophrenia and related psychotic disorders were coded as F20-F20.9 and schizoaffective subtypes under F25-F25.9. Alcohol use disorders were identified not only via the primary psychiatric code F10-F10.99 but also through related physiological and behavioral consequences, including E24.4 (alcohol-induced Cushing’s syndrome), G31.2, G62.1 (neurological conditions), and toxicological or external cause codes such as R78.0, X65-X65.9, and Y15-Y15.9. Similarly, drug use disorders were broadly classified using codes F11-F19.99, supplemented by neonatal and toxicological codes (P96.1, R78.1-R78.9). Lastly, depressive disorders were operationalized with codes F32-F33.9 (major depressive episodes and recurrent depression), along with dysthymic disorder categorized under F34.1.
Statistical analysis
To accurately assess and compare the burden of mental disorders across various populations and over time, we adopted a rigorous statistical framework designed to control for demographic differences, particularly those related to age structure. Recognizing that populations vary considerably in their age distributions, a factor that can significantly distort raw incidence and burden estimates, we applied age-standardized incidence rates (ASIRs) and age-standardized DALY rates (ASDRs). These standardized metrics were derived using the reference population structure recommended by the GBD study, thereby allowing for valid comparisons across regions, countries, and temporal intervals[13].
To identify and characterize temporal trends in mental disorder burdens from 1990 through 2021 (and with specific focus on the 2019-2021 COVID-19-impacted period), we employed the Joinpoint Regression Program (version 4.9.1.0). This method enables the detection of statistically significant inflection points, so-called “joinpoints”, where changes in the slope of trend lines suggest shifts in incidence or burden patterns over time. The model iteratively fits piecewise regression segments and uses permutation tests to determine the optimal number and location of joinpoints, thereby ensuring statistical robustness in trend interpretation[14,15].
All core statistical procedures, including data processing, regression modeling, and graphical visualizations, were implemented using the R statistical computing environment (version 4.2.3). Analyses adhered to a two-sided significance testing framework, and results with P value less than 0.05 were considered indicative of statistically significant findings. This threshold was consistently applied across all hypothesis tests to maintain analytical consistency and minimize type I error rates.
RESULTS
Global incidence of mental disorders
Tables 1 and 2 present a comprehensive summary of the global incidence patterns of mental disorders spanning the years 1990 to 2021. During this three-decade period, there was a substantial escalation in the total number of newly diagnosed mental disorder cases worldwide. By the year 2021, the global tally of new cases had surged to approximately 444.4 million, underscoring a significant and growing public health concern. In terms of standardized metrics, the ASIR exhibited a consistent upward trajectory over time. Specifically, the ASIR increased from 4737.97 per 100000 person-years in 1990 to 5459.77 per 100000 person-years in 2021. This translates to a 15.23% increase over the 30-year interval, indicating a persistent rise in the incidence of mental disorders on a global scale. Notably, a sharper acceleration was observed in the most recent years examined: Between 2019 and 2021, coinciding with the COVID-19 pandemic period, the ASIR rose by 16.08%, reflecting the potential exacerbating effect of the pandemic on mental health burdens (Table 1).
Table 1 Incidence of mental disorders, and percentage change of age-standardized rates by global burden of disease region.
Table 2 Disability-adjusted life-years of mental disorders in 2021, and percentage change of age-standardized rates by Global Burden of Disease region.
When disaggregated by SDI quintiles, all five SDI categories demonstrated increases in ASIR over time. Among them, countries classified within the low SDI group recorded the highest ASIR in 2021, reaching 6514.44 per 100000 person-years, suggesting a disproportionate burden in low-resource settings. In contrast, the high-middle SDI group exhibited the lowest ASIR at 4917.24 per 100000 person-years, pointing to potential protective effects associated with intermediate levels of development or health infrastructure. Geographically, all 21 GBD regions experienced an increase in incident mental disorder cases between 1990 and 2021. In 2021, the region with the highest ASIR was Central sub-Saharan Africa, where the rate soared to 8706.11 per 100000 person-years. This contrasts starkly with East Asia, which reported the lowest regional ASIR at 3340.99 per 100000 person-years in the same year. Over the full 30-year period, East Asia was the only region to show a decline in ASIR (-5.55%), suggesting possible improvements in prevention, reporting discrepancies, or other mitigating factors. Conversely, the largest long-term increase was observed in high-income North America, where the ASIR rose by an impressive 56.4%, potentially reflecting a combination of greater diagnostic awareness, increased mental health stressors, and changes in health-seeking behavior. Focusing on the shorter pandemic period from 2019 to 2021, the region with the most pronounced rise in ASIR was Andean Latin America, which experienced a surge of 31.37%, the fastest growth globally during this interval. These regional patterns are visually depicted in Figure 1A, which maps the global distribution of ASIR in 2021, highlighting areas of elevated incidence. At the national level, countries with the highest ASIRs in 2021 included Greenland, Palestine, Uganda, Greece, Angola, Lebanon, and the Central African Republic, all of which exhibited rates significantly above the global average. In contrast, some nations reported notably lower ASIRs, with Myanmar, the Democratic People’s Republic of Korea (North Korea), and China ranking among the lowest globally (Figure 1A). These disparities may reflect differences in diagnostic capacity, healthcare access, cultural perceptions of mental illness, or underreporting.
Figure 1 The burden of mental disorders across 204 countries and territories in 2021.
A: The age-standardized incidence rate in 204 countries and territories; B: The age-standardized disability-adjusted life years rate in 204 countries and territories; C: The age-standardized incidence rate in 21 global burden of disease regions by sexes; D: The age-standardized disability-adjusted life years rate in 21 global burden of disease regions by sexes. ASIR: Age-standardized incidence rate; ASDR: Age-standardized disability-adjusted life-year rate.
Global DALYs of mental disorders
As outlined in Table 2, the global burden of DALYs attributable to mental disorders demonstrated a marked increase over the study period, culminating in a total of approximately 155.4 million DALYs in the year 2021. This substantial disease burden reflects not only the widespread prevalence of mental disorders but also their significant impact on life quality and functionality across populations. The ASDR, a metric that adjusts for demographic differences and allows for cross-population comparisons, stood at 1909.14 per 100000 person-years in 2021. This figure represents a notable 73.52% increase relative to the baseline rate observed in 1990, indicating a long-term escalation in the years of healthy life lost due to mental illness. A closer examination of more recent trends reveals that between 2019 and 2021, a period marked by global pandemic disruptions, the DALY rate rose from 1738.12 (95% uncertainty interval: 1308.29-2210.63) to 1909.14 (95% uncertainty interval: 1440.15-2437.87), corresponding to a 12.25% rise over just two years (Table 2). When disaggregated by SDI quintiles, the high SDI group exhibited the highest ASDR in 2021, reaching 2276.02 per 100000 person-years, which likely reflects both enhanced diagnostic capacity and the increased recognition of mental disorders in developed regions. In contrast, the high-middle SDI group reported the lowest DALY rate, at 1806.88, possibly due to differences in healthcare infrastructure, mental health service accessibility, or social stigma. At the regional level, the Australasia region recorded the highest DALY burden, with an age-standardized rate of 2787.87, followed closely by high-income North America, where the rate reached 2662.06. These findings underscore the pervasive burden of mental illness in high-income regions, despite greater resource availability.
On the national scale, countries such as China, the Democratic People’s Republic of Korea (North Korea), and Viet Nam had the lowest reported ASDRs, potentially reflecting underdiagnosis or differences in mental health policy implementation. In stark contrast, the highest DALY rates were observed in Greenland, Greece, United States, and Australia, highlighting regional disparities in mental health outcomes (Figure 1B). Notably, a gender disparity was evident in 2021, with females consistently exhibiting higher age-standardized incidence and DALY rates for mental disorders compared to males. This sex-specific difference is illustrated in Figure 1C and D, suggesting that sociocultural roles, hormonal factors, or healthcare-seeking behavior may differentially influence mental health risks and outcomes between genders.
Global burden of 12 subtypes of mental disorders
This study further conducted a detailed stratified analysis of the global burden attributed to 12 specific subtypes of mental disorders, focusing on their ASDRs, incidence patterns, and temporal changes from 1990 to 2021, as well as during the COVID-19 pandemic window (2019-2021). In 2021, among all assessed subtypes, major depressive disorder (MDD) and anxiety disorders contributed the largest share of the global DALY burden. These two conditions remain the most prominent contributors to mental health-related disability across regions, underscoring their widespread prevalence and substantial impact on individuals’ quality of life and functional capacity. Over the broader timeline of 1990 to 2021, the ASDRs for MDD, anxiety disorders, and bulimia nervosa demonstrated consistent upward trends. In contrast, schizophrenia and bipolar disorder showed modest declines in ASDRs during the shorter period between 2019 and 2021, possibly indicating improved clinical management or shifts in diagnostic patterns. A clear gender-related pattern emerged across several mental disorder subtypes. In 2021, conditions such as MDD, anxiety disorders, bipolar disorder, and dysthymia were more commonly reported and imposed a higher burden on females compared to males, consistent with prior epidemiological evidence (Table 3).
Table 3 The global age-standardized disability-adjusted life-years for 12 mental disorders in 2021, and percentage change from 1990 to 2021.
In addition to overall DALY trends, we assessed the relative contribution of each subtype to the global and regional ASIR and DALY rate for the year 2021. Globally, MDD accounted for the highest proportion of ASIR, representing approximately 75.7% of all mental disorder-related incident cases. Anxiety disorders ranked second, contributing 12.4%. The highest regional concentration of MDD incidence was found in Central sub-Saharan Africa, where it constituted 86% of all mental disorder-related incident cases (Figure 2A). When analyzed by DALY burden, MDD again emerged as the leading contributor, accounting for approximately 30% of total DALYs globally. Regionally, Central sub-Saharan Africa recorded the highest proportion of DALYs due to MDD at 45.4%, followed by Eastern sub-Saharan Africa (39.6%), South Asia (36.8%), Southern sub-Saharan Africa (36.3%), and Western sub-Saharan Africa (34.6%). Notably, Tropical Latin America reported the highest share of anxiety disorder-related DALYs, contributing up to 40.8% of the regional burden (Figure 2A).
Figure 2 The age-standardized burden for the 12 subtypes of mental disorders across regions in 2021.
A: Age-standardized incidence rate percentage of the age-standardized rates for the 12 subtypes of mental disorders; B: Age-standardized disability-adjusted life-year rate percentage of the age-standardized rates for the 12 subtypes of mental disorders; C: Age-standardized incidence rate ranking of the age-standardized rates for mental disorders; D: Age-standardized disability-adjusted life-year rate ranking of the age-standardized rates for mental disorders. ASIR: Age-standardized incidence rate; ASDR: Age-standardized disability-adjusted life-year rate.
Figure 2B further illustrates the ranking of ASIR and DALY rates for all 12 mental disorder subtypes across the 21 GBD regions. In 13 of these regions, MDD was ranked as the top contributor to DALYs, reinforcing its global public health priority. In contrast, autism spectrum disorders held the top DALY rank in high-income Asia Pacific, reflecting regional variation in disorder prioritization and diagnostic emphasis. Interestingly, anorexia nervosa was the lowest-ranking subtype in terms of DALY contribution in 19 out of 21 GBD regions, indicating relatively lower prevalence or disability burden globally (Figure 2C and D).
The trends of mental disorders disease burden in regions with different SDI levels from 1990 to 2021
As previously discussed, the global burden of mental disorders has risen significantly over the past three decades. By 2021, the number of newly diagnosed cases of mental disorders had approximately doubled compared to that in 1990, signaling a sustained global increase in mental health challenges. Over this 30-year observation period, there was a 15.23% increase in the ASIR and an even more pronounced 73.52% rise in the ASDR, reflecting both rising case numbers and increasing years of healthy life lost due to mental disorders (Tables 1 and 2, Figure 3A and B). Notably, both males and females exhibited upward trajectories in mental disorder burden, although the female population consistently showed higher ASIR and DALY values across the entire study period. This gender disparity may be attributable to differential vulnerability to specific psychiatric conditions, gender-based exposure to psychosocial stressors, and variations in help-seeking behaviors.
Figure 3 Trend of the age-standardized rates of mental disorders in 1990-2021.
A: Temporal trends in the sex-specific age-standardized incidence rate in global and all the socio-demographic index (SDI) regions; B: Temporal trends in the sex-specific age-standardized disability-adjusted life-years rate in global and all the SDI regions; C: The age-standardized rates of mental disorders in 21 global burden of disease regions by SDI; D: The age-standardized disability-adjusted life-year rate of mental disorders in 21 global burden of disease regions by SDI. For each region, points from left to right depict estimates from each year from 1990 to 2021. The black line represents the average expected relationship between SDI and burden estimates rates for mental disorders based on values from each geographical region over the 1990-2021 estimation period. ASIR: Age-standardized incidence rate; SDI: Socio-demographic index; ASDR: Age-standardized disability-adjusted life-year rate.
The observed temporal trends differed markedly across regions stratified by SDI quintiles. The most conspicuous surge in both ASIR and DALY rates occurred after 2019, coinciding with the onset of the COVID-19 pandemic. Prior to this period, high and high-middle SDI regions experienced a gradual increase in the incidence of mental disorders. However, post-2019, these regions saw a steep escalation, likely driven by pandemic-related disruptions in social routines, economic security, and access to mental health services.
Conversely, low and low-middle SDI regions displayed fluctuating incidence trends. These areas experienced a peak around 2005, followed by a decline in incidence that persisted for more than a decade before a renewed increase was observed beginning in 2019. Despite these oscillations, the ASIRs in low and low-middle SDI regions have consistently remained above the global average, possibly reflecting under-resourced healthcare systems, higher exposure to conflict and trauma, and limited mental health awareness. With regard to the DALY rate, three SDI groups, high, low-middle, and low SDI regions, reported values that exceeded the global average, highlighting the severity of the impact in both resource-rich and resource-constrained settings. In contrast, middle and high-middle SDI regions exhibited DALY rates lower than the global mean, potentially reflecting more moderate exposure to both risk factors and healthcare access variability. These patterns underscore the importance of adopting context-sensitive mental health strategies, as the scale and nature of the burden are not uniform across developmental stages and healthcare capacities of different world regions.
Mental disorders incidence and DALYs in relation to SDI
To further investigate how development levels influence mental disorder burden, Figure 3C and D juxtaposes the observed ASIR and ASDRs with their expected values based on regional SDI levels. The relationship between mental disorder metrics and SDI was found to be nonlinear, illustrating that economic and social development does not translate into mental health burden reduction in a simple or uniform manner. Globally, a large number of regions generally aligned with the expected incidence and DALY levels derived from their SDI status. However, substantial regional heterogeneity was observed, with some areas consistently falling below expected thresholds, indicating a lower-than-anticipated burden, while others consistently exceeded these predictions. Importantly, these deviations from expectation were not static; several regions demonstrated fluctuating or even declining trends over time, only to surge again after 2019. For instance, regions such as Eastern Europe, high-income North America, and Australasia reported DALY rates that remained above SDI-predicted values, despite experiencing intermittent reductions in earlier years. These elevated burdens may be linked to complex sociocultural, economic, or healthcare-related dynamics, including high prevalence of mood and substance use disorders, insufficient integration of mental health into primary care, or socioeconomic stressors.
Crucially, all 21 GBD regions experienced a sharp escalation in both ASIR and DALY rates from 2019 to 2021, regardless of their baseline trends or SDI alignment. This global surge is likely a direct consequence of the COVID-19 pandemic, which intensified mental health risks through mechanisms such as social isolation, unemployment, bereavement, and disruption of routine health services. In summary, while SDI provides a useful framework for understanding broad trends in disease burden, it does not fully capture the complex interplay of determinants that shape mental health trajectories across the globe. These findings emphasize the necessity of tailored mental health policies and interventions, especially during global crises, to prevent widening inequities in mental health outcomes.
DISCUSSION
Mental disorders have long constituted a profound and growing challenge to global public health systems. Drawing upon the comprehensive data from the GBD 2021 study, our analysis systematically explored the longitudinal and spatial dynamics of mental disorder burden at the global, regional, and national levels over the past three decades. Overall, findings indicate that between 1990 and 2021, both the incidence and DALY burden of mental disorders exhibited a general upward trajectory, with notable heterogeneity across populations, gender groups, and SDI categories.
From the perspective of different genders, consistent with the previous research results[16], we observed that in various countries and regions, the incidence rate and DALY for women consistently exceed those for men. This disparity may be attributed to several factors: Firstly, women are disproportionately affected by gender-based violence, lower social status, and other societal challenges, which contribute to prolonged chronic stress. Additionally, the diagnosis rate of anxiety disorders among women is approximately twice that of men[17,18]. Secondly, in developing countries, women are often expected to fulfill traditional family roles while balancing career development and societal expectations, which further exacerbates their psychological burden[19,20]. However, gender bias in mental health services often results in female patients experiencing overdiagnosis (e.g., of emotional disorders) or inadequate treatment[21,22]. For instance, research in Saudi Arabia indicates that global mental health studies frequently overlook gender differences[23]. Additionally, women are more likely to be trapped in a “social causal chain”, where low economic status contributes to the development of mental health symptoms, which, in turn, further restrict their economic opportunities[24,25]. Studies in Nepal have also shown that the prevalence of mental health issues among women is higher than that among men, with a strong correlation to socioeconomic factors such as low education and unemployment[26].
From the perspective of different SDI levels, research indicates that 2019 represents a key turning point. After this period, the incidence rate of mental disorders sharply increased in high- and middle-SDI regions, while the rise in low- and middle-SDI regions was more gradual. This trend may be linked to the psychological impact of the COVID-19 pandemic. Literature suggested that high-SDI regions, such as North America and Australia, experienced significantly higher-than-expected ASIR for anxiety and depression between 2019 and 2021, likely due to factors such as social isolation, economic pressure, and psychological stress associated with the pandemic[27,28]. For example, Bulgaria exhibited the highest growth rate in the burden of anxiety disorders, with a change rate of 0.32[27]. Moreover, the well-developed healthcare systems in high-SDI areas contribute to higher rates of mental disorder screening and diagnosis[29,30]. However, the pandemic may have exacerbated the strain on existing mental health services, leading to a concentration of unmet needs. In contrast, the incidence rate of mental disorders in middle- and low-SDI regions gradually declined after 2005, which could be attributed to rapid urbanization or economic fluctuations during that period, resulting in increased psychological stress[31,32]. For instance, the mental disorder burden in the Middle East and North Africa region is significantly influenced by ongoing conflicts and demographic changes[32]. Overall, the ASIR in low- and middle-SDI regions remains higher, potentially due to factors such as limited healthcare resources, higher comorbidity rates of chronic conditions (e.g., non-alcoholic fatty liver disease and mental disorders), and more prevalent risk factors like air pollution and malnutrition[8,10,33-35].
At the national and regional level, our study found that China has one of the lowest incidence rates of mental disorders and DALYs, while Greenland, Greece, United States, and Australia exhibit the highest incidence rates. These findings are consistent with previous research[36]. The lowest incidence rates are observed in certain regions of sub-Saharan Africa and Asia, which aligns with earlier studies[37]. A plausible explanation for China’s low incidence rate is the government’s sustained focus on mental health, which has resulted in a series of policies aimed at addressing mental health issues. For instance, China has been consistently introducing mental health-related policies since 1987, with an exponential increase in policy initiatives over time. Initially focused on severe mental disorders, these policies have gradually expanded to encompass common psychological problems and include multiple dimensions such as service system development and organizational management[38]. Additionally, the 2013 implementation of China’s Mental Health Law represents one of the few instances globally where the principles of the United Nations Convention on the Rights of Persons with Disabilities were localized. The law explicitly prohibits involuntary treatment unless there is an immediate danger, reflecting a human rights-oriented approach that may reduce stigma and encourage individuals to seek help[39,40]. China has also incorporated mental health services into its primary healthcare system through the “Healthy China 2030” strategy, which includes measures such as authorizing family doctors to prescribe antidepressants[41] and promoting psychiatric resources in tertiary hospitals[42,43]. Furthermore, Chinese policies emphasize localized service models, such as integrating traditional Chinese medicine for emotional regulation into community mental health services[38]. Given China’s large population, its low incidence rate of mental disorders may be a significant contributor to the lower incidence rate observed across East Asia. However, the low coverage of epidemiological data in sub-Saharan Africa and parts of Asia introduces greater uncertainty in the estimated values[36]. The high incidence rates of mental disorders in Greenland, Greece, United States, and Australia may be influenced by various factors. In Greenland, the limited social activities and prolonged winter polar nights are likely contributing factors[44]. In Greece, barriers to accessing healthcare resources may play a significant role[45], while in United States, rising diagnostic rates, social pressures, and inequality have been identified as potential causes[30,46]. In Australia, the uneven distribution of mental health resources may contribute to the high incidence rates observed[47].
From the classification of mental disorders, MDD and anxiety disorders emerged as the most prevalent and burdensome subtypes globally. In 2021, they accounted for approximately 46.02 million and 42.51 million DALYs, respectively, consistent with findings from prior studies[48,49]. Several factors contribute to their prominent disease burden. Both conditions typically begin during adolescence or early adulthood and often follow a chronic or relapsing course, leading to long-term functional impairment. MDD has been identified as the leading cause of disability from as early as age 10, while anxiety disorders present the highest incidence among adolescents, affecting an estimated 932 million individuals aged 10-24 worldwide[50]. This early onset and persistence contribute to a cumulative increase in DALYs over time[51,52]. Beyond individual pathology, the burden of these disorders is further amplified by social and environmental stressors, including urbanization, social isolation, and public health emergencies such as the COVID-19 pandemic, all of which have been shown to heighten the risk and severity of depressive and anxiety symptoms[49,53]. Moreover, improvements in disease detection, diagnostic practices, and the methodological rigor of the GBD study may also account for the observed increase in DALY estimates, reflecting enhanced recognition and reporting rather than purely a rise in true incidence[54]. These disorders also carry substantial socioeconomic consequences, contributing to reduced productivity, disrupted education, and long-term unemployment. Such impacts create a vicious cycle where poor mental health and economic disadvantage reinforce one another[55]. Overall, these findings underscore the urgent need to prioritize MDD and anxiety disorders in global mental health policy, with targeted strategies for early intervention, sustained treatment, and integrated social support, especially among young populations who are disproportionately affected.
In this analysis, we observed a continuous and marked rise in the burden of MDD and anxiety disorders following the onset of the COVID-19 pandemic. This trend may be linked to rising rates of severe acute respiratory syndrome coronavirus 2 infection and reduced population mobility[56]. Evidence suggests that severe acute respiratory syndrome coronavirus 2 infection may contribute to the onset of mental health conditions and suicidal behaviors[57,58]. During the pandemic, many individuals faced stressful or traumatic experiences such as enforced isolation, infection, and quarantine measures. These conditions are known to heighten anxiety and depressive symptoms, disrupt sleep patterns, and lower overall quality of life[59].
We also noted that while schizophrenia remains a major contributor to global DALYs, its ASDR showed minimal variation globally, with a slight decline noted from 2019 to 2021. Despite the substantial overall DALY count due to schizophrenia, reflecting its chronic nature and associated premature mortality[60], the stable or slightly declining age-standardized rate may be due to several reasons. First, the standardization process eliminates differences related to demographic aging. Although patient numbers have grown, especially in high-SDI countries[61], natural mortality patterns, particularly among older populations, might counterbalance this growth[62]. Second, as schizophrenia typically presents in early adulthood (ages 25-34), its impact may be diluted in age-standardized metrics, which average contributions across age brackets[63].
However, this study has several limitations. One major challenge is the lack of comprehensive primary data in low-resource areas, especially in sub-Saharan Africa, where figures rely heavily on modeling and are therefore subject to higher uncertainty. Additionally, this study did not delve into the diverse factors influencing mental health. Future investigations should aim to clarify the contributions of specific risk factors. Although GBD 2021 treats COVID-19 as a distinct condition with limited direct ties to mental disorders, the pandemic’s broad disruptions to healthcare delivery have likely impacted diagnosis and treatment of psychiatric conditions. These disruptions are expected to elevate the global mental health burden in the aftermath of the pandemic. Nevertheless, the short duration since COVID-19’s emergence may not yet reflect the full scope of these effects. Longitudinal studies will be essential to evaluate the lasting consequences of the pandemic on mental health by comparing pre- and post-pandemic data[56-63].
CONCLUSION
The results of this study highlight the staggering global, regional, and national burden of mental disorders, which continues to rise, particularly following the COVID-19 pandemic. The burden also exhibits significant heterogeneity across sexes and geographic regions. These findings underscore the urgent need for policymakers to develop and strengthen targeted prevention strategies that consider local demographic factors and gender differences. Key recommendations include integrating mental health services into primary healthcare systems, such as community health centers, and promoting remote mental health services and mobile health applications. To effectively reduce the incidence of mental disorders, it is essential to implement programs for emotional regulation and stress management, provide economic support combined with mental health services for low-income populations, especially women, and focus on life-cycle prevention strategies.
Footnotes
Provenance and peer review: Invited article; Externally peer reviewed.
Peer-review model: Single blind
Specialty type: Psychiatry
Country of origin: China
Peer-review report’s classification
Scientific Quality: Grade A, Grade B, Grade C
Novelty: Grade A, Grade C, Grade C
Creativity or Innovation: Grade B, Grade C, Grade C
Scientific Significance: Grade A, Grade A, Grade C
P-Reviewer: Li JY; Rong J; Zhang BR S-Editor: Wu S L-Editor: A P-Editor: Yu HG
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