Brasil : Estudo de Carga Global de Doença , 1990 e 2015 The Burden of disease attributable to mental and substance use disorders in Brazil : Global Burden of Disease Study , 1990 and 2015

Rev BRas epidemiol maio 2017; 20 sUppl 1: 191-204 RESUMO: Introdução: Os transtornos mentais e decorrentes do uso de substâncias psicoativas (TM) são altamente prevalentes, gerando elevado custo social e econômico. Objetivo: Descrever a carga dos TM no Brasil e Unidades Federativas (UFs), em 1990 e 2015. Métodos: Estudo descritivo da carga de doença dos TM, por meio de estimativas padronizadas por idade do Global Burden of Disease Study 2015: anos de vida perdidos por morte prematura (YLL); anos vividos com incapacidade (YLD); e anos de vida perdidos por morte ou incapacidade (DALY=YLL+YLD). Resultados: No Brasil, apesar da baixa taxa de mortalidade, observa-se alta carga para os TM desde 1990, com elevados YLD. Em 2015, esses transtornos foram responsáveis por 9,5% do total de DALY, ocupando a 3a e a 1a posições na classificação de DALY e YLD, respectivamente, com destaque para os transtornos depressivos e de ansiedade. Os transtornos decorrentes do uso de drogas apresentaram a maior elevação das taxas de DALY entre 1990 e 2015 (37,1%). A maior proporção de DALY ocorreu na idade adulta e no sexo feminino. Não houve diferenças substanciais na carga dos TM entre as UFs. Conclusão: Apesar da baixa mortalidade, os TM são altamente incapacitantes, indicando necessidade de ações preventivas e protetivas, principalmente na atenção primária em saúde. A homogeneidade das estimativas em todas as UFs, obtidas a partir de estudos realizados majoritariamente nas regiões Sul e Sudeste, provavelmente não reflete a realidade do Brasil, e indica necessidade de estudos em todas as regiões do país.


INTRODUCTION
Mental and substance use disorders (MD) affect an average of 26.1% of the adult population in 17 countries worldwide 1 , generating high social and economic costs, which in turn have important implications for health care planning [2][3][4] .Nevertheless, most low-and middle-income countries, such as Brazil, spend less than US$2.00 per capita on the treatment and prevention of mental disorders.High-income countries spend on average more than US$50.00 5 .In Brazil, data from the National Health Survey (acronym in Portuguese -PNS) demonstrated inequities in access to mental health care.In addition, it was found that the majority of Brazilians with clinically relevant depressive symptoms (78.8%) did not undergo any type of treatment 6 .
With the publication of the results of the first Global Burden of Disease (GBD) study in 1996, the impact of prevalent and disabling disorders with lower mortality, such as MD, have emerged as a serious public health problem.In this study, 5 of the 10 leading causes of years lived with disability (YLD) worldwide were in the following category: depressive disorders (13.0%), alcohol use disorders (7.1%), schizophrenia (4.0%), bipolar disorder (3.3%), and obsessive compulsive disorder (2.8%) 7 .
Rev BRas epidemiol maio 2017; 20 sUppl 1: 191-204 In Brazil, there are few representative population studies that provide prevalence estimates for MD [12][13][14][15][16][17][18][19][20] .A study with a representative sample of adults from the city of São Paulo and its metropolitan region 21 found a prevalence of 29.6% of MD in the last 12 months with anxiety (19.9%) and mood disorders (11.0%) as the most prevalent, followed by impulse control disorders (4.2%) and substance use disorders (3.6%).However, there are few prevalence studies that evaluate different regions of the country combined with mortality data by MD [22][23][24][25] .In this respect, it is important to know and measure the impact of the MD burden on the different Brazilian Federated Units (FUs), considering the wide cultural and socioeconomic diversity in the country.
The objective of this study was to describe the data related to the burden of mental and substance use disorders, by age and sex, in the years 1990 and 2015, in Brazil and its FUs.

METHODS
A descriptive study was carried out with secondary data regarding MD burden estimated for Brazil in the GBD 2015 study, which was coordinated by the Metrics and Health Assessment Institute (IHME), University of Washington (United States of America -USA) 10 .In this study, the variations in burden according to type of mental disorder, age, sex, year (1990 and 2015), and FU of Brazil will be explored.More detailed information on the data and methods used to generate the estimates can be obtained in other publications 10,11.In GBD 2015, MD were defined according to the diagnostic criteria described either in the International Statistical Classification of Diseases and Health Related Problems (ICD-10) 26 or in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV TR) 27 , and their correlates for the 1990 data.In total, there are 12 groups of disorders: Years of life lost (YLL) added to the YLD indicators resulted in the DALY measurement.For all estimates, uncertainty intervals of 95% (95% UI) were considered 10 .
The YLL calculation, which expresses the effect of premature deaths on the population, was performed by multiplying the number of MD deaths, for each age group, by the highest life expectancy at that age, regardless of sex 28 .In Brazil, the main source of mortality data is the Ministry of Health's Mortality Information System (SIM).In estimating YLL, the GBD 2015 followed the ICD-10's 26 cause of death categories, in which deaths can only be attributed to a given condition when it is considered a direct cause of death.Details on the methodology used for the calculation of YLL in GBD 2015 can be seen in other publications 28 .
YLLs were estimated only for schizophrenia, eating disorders, and substance use disorders considered by the ICD-10 26 as direct causes of death.For the other groups of mental disorders, the burden is solely due to the incapacity caused by such disorders, so that the DALY rates are matched to the YLD values 29,30 .
The calculation of YLDs, which express morbidity in terms of unhealthy years of life due to health problems or disabilities, was performed by multiplying two components: the prevalence of mental disorders in the population and the "disability weight," which reflects the severity of health loss associated with the MD on a scale from 0 (perfect health) to 1 (equivalent to death).The prevalence of each disorder was obtained using data from Brazilian population-based studies.The GBD 2015 used the same weights assigned to the severity of each disorder as the GBD 2013.The methodology and the articles used as sources of data for the estimates and for the values of the weights assigned to each disease are available in other publications 11 .
In this study, the focus of the results will be the presentation of the DALYs produced by the MD category, resulting from the sum of the YLLs and the YLDs.To compare the indicators between the years of 1990 and 2015, the age-standardized rates of DALY by the MD were estimated.In addition, the classification by disorder and by FU according to the values of DALY standardized by age was performed.
The Global Burden of Disease Study -GBD Brazil 2015 -was approved by the Research Ethics Committee of the Universidade Federal de Minas Gerais (CAAE Project -62803316.7.0000.5149).

RESULTS
In the GBD 2015, the MD category accounted for 9.5% of the total DALY for all causes in Brazil.Depressive disorders accounted for the highest proportion of DALY (3.3%) and ADHD accounted for the lowest proportion (0.02%).In both sexes, changes in DALY between 1990 and 2015 were attributable to growth and aging of the population, as both age-standardized rates in the period were within the range of uncertainty (95% UI).However, it is important to highlight the 37.1% increase in DALY rates due to drug use disorders between 1990 and 2015 observed in both sexes (Table 1).
MD were the main cause of disability in Brazil, both in 1990 and in 2015, accounting for 24.9% of the total YLD for all causes (Table 2).In 2015, the category became the third leading cause of DALY in Brazil, rising three places in the ranking in relation to 1990.From 1990 to 2015, the entire category of MD and almost all disorders on their own rose in rank  in the classification of DALY and YLD.In particular, it is important to note the increase in the DALY positions of depressive and anxiety disorders from 12th and 14th positions in 1990 to 8th and 10th positions in 2015, respectively (Table 2).MD affected all age groups, with the highest proportion of DALYs in both sexes occurring in adulthood (Figure 2).In both sexes, DALY rates for depressive disorders and for anxiety disorders peaked in adulthood.However, the burden of depressive disorders was greater among those aged 30-34 years, and the burden of anxiety disorders, was greater among those aged between 40 and 44 years.
The burden associated with less common chronic disorders, such as schizophrenia and bipolar disorder, gradually increased up until adulthood, with a peak between 40 and 44 years and 25 and 29 years of age, respectively.In relation to the drug use di orders, the burden was higher among young adults (20-24 years).For alcohol use disorders, the highest burden occurred between 45 and 49 years of age, followed by a gradual decline (Figure 2).
Boys younger than 10 years old had a higher proportion of DALYs than girls of the same age.This difference was more evident in the case of autism spectrum disorders and conduct disorder, with a load of 2.5 times higher than for girls.Among the age group of 10-14 years, women had a greater burden for depressive disorders and anxiety disorders than men.In all age groups, men presented a greater burden for schizophrenia and substance use disorders.The highest proportion of DALYs in women occurred in the age range between 40 and 44 years, and in men, it occurred between the ages of 35 and 39 years (Figure 2). Figure 3 shows the MD burden in Brazil and in each FU.Depressive disorders demonstrated the highest proportion of burden in all the FUs, followed by anxiety disorders.The DALYs of disorders resulting from alcohol use presented the greatest regional variation: DALY rates in Ceará and Sergipe were almost four times higher than in Pará.In contrast, the other mental disorders and the drug use disorders demonstrated homogeneous rates in terms of the proportion of DALYs (less than twofold among FUs) in 2015.With the exception of alcohol use disorders, the other age-standardized DALY rates for FUs did not diff er substantially from the national average.

DISCUSSION
The results of the GBD 2015 indicate that MD are the third cause of disease burden in Brazil, behind only cardiovascular diseases and cancers.Furthermore, it was found that they contribute considerably to the loss of health in individuals of all ages.The GBD's study methodology, addressing both mortality and disability, has made MD more visible as a relevant public health problem, which has allowed for advances in research concerning their prevalence and associated risks.By 2015, MD were responsible for a high burden of disease throughout the world 10 .MD jumped from eighth to sixth place between 1990 and 2015 in the DALY world ranking.In Brazil, DALY by MD moved from sixth to third position, indicating a more serious situation regarding mental health in the country.
DALY by MD is clearly related to disability -not mortality.Whereas throughout the world MD have placed second in the classifi cation of disability since 1990, behind only musculoskeletal disorders, in Brazil they are already the main cause.Depressive and anxiety disorders continued to be among the top 10 causes of disability in Brazil and worldwide in 2015 11 .
Depressive and anxiety disorders, which were highly prevalent and incapacitating, stood out in the classifi cation of YLD and, consequently, DALY.However, some disorders, although very disabling for the individual, did not stand out in the YLD classifi cation due to their low prevalence in the population, such as schizophrenia, which presented the highest disability weight of all diseases evaluated in 2015.However, it was not prominent in terms of YLD because of its low prevalence 11 .
Notably in Brazil, anxiety disorders have the highest rates of YLD and DALY in the world 31 .These results are consistent with the studies 14,15,17,20,21 used by the GBD researchers to make such estimates.One of these studies 21 found a greater prevalence of anxiety disorders in   Brazil compared with 23 other countries.The possible explanations for the high prevalence in the country include widespread urban violence, adverse socioeconomic conditions, pollution, high noise level, and a lack of leisure areas in Brazilian cities.
In developing regions, such as in Brazil, there are a larger number of people in the age groups where MD are most prevalent.This demographic and epidemiological transition contributes to the increase in the absolute burden of these disorders in the population 8 .However, for most MD, the increase in the absolute number of DALYs was not accompanied by the increase in age-standardized DALY rates, which means that changes in DALY between 1990 and 2015 were almost entirely attributable to growth and the aging of the population.Nevertheless, the stability in the age-standardized rate demonstrates the need for the country to tackle this problem, which tends to grow with demographic transitions.
It is important to consider that the drug use disorders had the highest increase in DALY rates between 1990 and 2015 (37.1%) and affected mainly young men.Abdalla et al. (2014)  33 indicate that the prevalence rate of crack cocaine use among Brazilians aged 14 years and over, in 2012 was 2.2% in the last 12 months, and they suggest that the country is among the nations with the highest rates of annual consumption, as it is one the largest consumer markets of cocaine in the world.
The results of the GBD 2015 reflect the reality of Brazilian epidemiological studies [12][13][14]16,18,19,21,22 in which women are more affected by depressive disorders and anxiety disorders, whereas men are more affected by schizophrenia, alcohol and drug use disorders, and ADHD in childhood and adulthood. These results oincide with the results of most studies conducted in Western countries 16 .
Another important result of the GBD 2015's Brazilian data was the high burden of mental disorders that occur in childhood and adolescence, such as autism spectrum disorders, ADHD, and conduct disorders.These results reinforce the need for prevention and treatment services aimed at children and adolescents, which are currently scarcely available in Brazil 34 .
In this context, the results of this study highlight the challenge that MD represent for the country's health system.In Brazil, the implementation of the community mental health services network began in the 1990s and, although it is constantly growing, there are still insufficient services for effective care for the entire population 35 .In addition, there are cultural, financial, and structural barriers that prevent people from seeking psychiatric care, such as stigma, little knowledge of the disease, prejudice, disbelief in treatment, and lack of training for primary care teams in the identification of cases, among others 18 .
The Brazilian territory is special because it is marked by important differences in the availability of mental health services depending on the region of the country.The national population-based survey (PNS) conducted in 2013, reported estimates of access to treatment for depression, and found that in the north region there is the largest proportion of untreated individuals (90.2%) whereas in the south region the lowest proportion of untreated individuals (67.5%) 6 .Nevertheless, the results of the GBD 2015 for Brazilian FUs were practically homogeneous.This is because burden of disease estimates were generated based on data available from FUs, which traditionally tends to be performed in urbanized areas and in FUs in the southeast and south regions, which certainly do not reflect the reality of the entire country.It is important to note that the results of the GBD give the country an opportunity to critically assess the quality of its data, in a way that its limited availability needs to be considered when interpreting specific regions.
As a future possibility, the use of population-based data sources such as the National Household Sample Survey (acronym in Portuguese -PNAD) of the Brazilian Institute of Geography and Statistics (IBGE) 36 is compelling, as it is a survey that is representative on a national and an urban-rural level, and it covers approximately 150 thousand households and more than 350 thousand people in the 27 FUs of Brazil.The PNS, based on the PNAD database, unlike the GBD 2015, found important differences among Brazilian FUs regarding the presence of depressive symptoms in the population 37 .
A characteristic of the GBD methodology, which had an impact on the low number of YLLs generated by the MD category, consists in attributing mortality to a single disease/ cause, as well as in the fact that YLLs have only been estimated for schizophrenia, eating disorders, and alcohol and drug use disorders, considered by the ICD-10 26 as direct causes of death 28 .It is for this reason that, for most MD, the DALYs are basically YLD.
Globally, MD accounted for only 0.5% of deaths by all causes in 2015, according to the GBD.This finding provides a contrast with a recent systematic review study which, when considering the excess mortality associated with mental disorders, estimated that 14.3% of deaths worldwide are attributable to these disorders.According to this study 38 , people with mental disorders have a mortality rate of 2.2 times higher than the general population.The reduction in the life expectancy of those with mental disorders is, on average, 10.1 YLL, regardless of the cause of death.These data suggest that there is a large burden of mental disorders associated with mortality that is underestimated.
Considering that many MD are frequently co-morbid with other highly prevalent and disabling diseases, such as cardiovascular diseases and diabetes 35 and are important risk factors for suicide (approximately 80% of suicide deaths are attributable to MD 8 ), it is suggested that alternative approaches to methodology should be explored, such as the quantification of the proportion of death attributable to MD as risk factors for other health outcomes 8,39 .A study devoted to estimating the DALYs of suicide attributed to the category of MD in the GBD 2010 concluded that the inclusion of DALYs attributable to suicide would have increased the overall burden of these disorders from 7.4% to 8.3%.This would result in a change of category in the overall classification, from the fifth to the third cause of disease burden 39 .
Finally, it is important to highlight that the standardized methodology of the GBD analysis makes it possible to produce indicators that allow for the comparison of data between different regions and countries of the world.In addition, estimates of temporal trends provide more consistent information for health planning, in the medium and long term, when compared to point estimates 40 .

Figure 1 .
Figure 1.Proportion of DALY a , YLD b e YLL c for each group of mental and substance use disorders in 2015.

Figure 2 .
Figure 2. Years lost due to premature death or disability (DALY b ), for each mental and substance use disorders in 2015, by sex and age, in Brazil.a) ADHD: Attention deficit hyperactivity disorder b) DALY: Disability-Adjusted Life-Years

Figure 3 .
Figure 3. DALY b rate per 100 thousand individuals for : mental and substance use disorders in 2015, for Brasil and its Federated Units.
DALY b per 100,000 a) ADHD: Attention deficit hyperactivity disorder b) DALY: Disability-Adjusted Life-Years

Table 1 .
DALY a rates per 100,000 individuals attributable to each mental and substance use disorders and percentages of change from 1990 to 2015 in men, women, and both sexes in Brazil.
a) DALY: Disability-Adjusted Life Years; b) Percentage of total DALY for all causes, for both sexes; c) Interval rates of uncertainty (95% UI) with intersection; d) DM: Mental and substance use disorders; e) ADHD: Attention deficit hyperactivity disorder.

Table 2 .
Classification of DALY a and YLD b of each mental and substance use disorders in 1990 and 2015, in relation to the rates standardized by age.
a) DALY: Disability-Adjusted Life Years; b) YLD: Years Lived With Disability; c) MD: Mental and substance use disorders; d) ADHD: Attention deficit hyperactivity disorder.