Harvey Whiteford

Global burden of disease attributable to mental and substance use disorders: findings from the Global Burden of Disease Study 2010

BACKGROUND We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2010 (GBD 2010) to estimate the burden of disease attributable to mental and substance use disorders in terms of disability-adjusted life years (DALYs), years of life lost to premature mortality (YLLs), and years lived with disability (YLDs). METHODS For each of the 20 mental and substance use disorders included in GBD 2010, we systematically reviewed epidemiological data and used a Bayesian meta-regression tool, DisMod-MR, to model prevalence by age, sex, country, region, and year. We obtained disability weights from representative community surveys and an internet-based survey to calculate YLDs. We calculated premature mortality as YLLs from cause of death estimates for 1980-2010 for 20 age groups, both sexes, and 187 countries. We derived DALYs from the sum of YLDs and YLLs. We adjusted burden estimates for comorbidity and present them with 95% uncertainty intervals. FINDINGS In 2010, mental and substance use disorders accounted for 183·9 million DALYs (95% UI 153·5 million-216·7 million), or 7·4% (6·2-8·6) of all DALYs worldwide. Such disorders accounted for 8·6 million YLLs (6·5 million-12·1 million; 0·5% [0·4-0·7] of all YLLs) and 175·3 million YLDs (144·5 million-207·8 million; 22·9% [18·6-27·2] of all YLDs). Mental and substance use disorders were the leading cause of YLDs worldwide. Depressive disorders accounted for 40·5% (31·7-49·2) of DALYs caused by mental and substance use disorders, with anxiety disorders accounting for 14·6% (11·2-18·4), illicit drug use disorders for 10·9% (8·9-13·2), alcohol use disorders for 9·6% (7·7-11·8), schizophrenia for 7·4% (5·0-9·8), bipolar disorder for 7·0% (4·4-10·3), pervasive developmental disorders for 4·2% (3·2-5·3), childhood behavioural disorders for 3·4% (2·2-4·7), and eating disorders for 1·2% (0·9-1·5). DALYs varied by age and sex, with the highest proportion of total DALYs occurring in people aged 10-29 years. The burden of mental and substance use disorders increased by 37·6% between 1990 and 2010, which for most disorders was driven by population growth and ageing. INTERPRETATION Despite the apparently small contribution of YLLs--with deaths in people with mental disorders coded to the physical cause of death and suicide coded to the category of injuries under self-harm--our findings show the striking and growing challenge that these disorders pose for health systems in developed and developing regions. In view of the magnitude of their contribution, improvement in population health is only possible if countries make the prevention and treatment of mental and substance use disorders a public health priority. FUNDING Queensland Department of Health, National Health and Medical Research Council of Australia, National Drug and Alcohol Research Centre-University of New South Wales, Bill & Melinda Gates Foundation, University of Toronto, Technische Universität, Ontario Ministry of Health and Long Term Care, and the US National Institute of Alcohol Abuse and Alcoholism.

Resources for mental health: scarcity, inequity, and inefficiency

Resources for mental health include policy and infrastructure within countries, mental health services, community resources, human resources, and funding. We discuss here the general availability of these resources, especially in low-income and middle-income countries. Government spending on mental health in most of the relevant countries is far lower than is needed, based on the proportionate burden of mental disorders and the availability of cost-effective and affordable interventions. The poorest countries spend the lowest percentages of their overall health budgets on mental health. Most care is now institutionally based, and the transition to community care would require additional funds that have not been made available in most countries. Human resources available for mental health care in most low-income and middle-income countries are very limited, and shortages are likely to persist. Not only are resources for mental health scarce, they are also inequitably distributed-between countries, between regions, and within communities. Populations with high rates of socioeconomic deprivation have the highest need for mental health care, but the lowest access to it. Stigma about mental disorders also constrains use of available resources. People with mental illnesses are also vulnerable to abuse of their human rights. Inefficiencies in the use of available resources for mental health care include allocative and technical inefficiencies in financing mechanisms and interventions, and an overconcentration of resources in large institutions. Scarcity of available resources, inequities in their distribution, and inefficiencies in their use pose the three main obstacles to better mental health, especially in low-income and middle-income countries.

2007 National Survey of Mental Health and Wellbeing: methods and key findings.

Objective: To provide a description of the methods and key findings of the 2007 Australian National Survey of Mental Health and Wellbeing. Method: A national face-to-face household survey of 8841 (60% response rate) community residents aged between 16 and 85 years was carried out using the World Mental Health Survey Initiative version of the Composite International Diagnostic Interview. Diagnoses were made according to ICD-10. Key findings include the prevalence of mental disorder, sex and age distributions of mental disorders, severity of mental disorders, comorbidity among mental disorders, and the extent of disability and health service use associated with mental disorders. Results: The prevalence of any lifetime mental disorder was 45.5%. The prevalence of any 12 month mental disorder was 20.0%, with anxiety disorders (14.4%) the most common class of mental disorder followed by affective disorders (6.2%) and substance use disorders (5.1%). Mental disorders, particularly affective disorders, were disabling. One in four people (25.4%) with 12 month mental disorders had more than one class of mental disorder. One-third (34.9%) of people with a mental disorder used health services for mental health problems in the 12 months prior to the interview. Conclusions: Mental disorders are common in Australia. Many people have more than one class of mental disorder. Mental disorders are associated with substantial disability, yet many people with mental disorders do not seek help for their mental health problems.

Global burden of disease attributable to illicit drug use and dependence: findings from the Global Burden of Disease Study 2010.

BACKGROUND No systematic attempts have been made to estimate the global and regional prevalence of amphetamine, cannabis, cocaine, and opioid dependence, and quantify their burden. We aimed to assess the prevalence and burden of drug dependence, as measured in years of life lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life years (DALYs). METHODS We conducted systematic reviews of the epidemiology of drug dependence, and analysed results with Global Burden of Diseases, Injuries, and Risk Factors Study 2010 (GBD 2010) Bayesian meta-regression technique (DisMod-MR) to estimate population-level prevalence of dependence and use. GBD 2010 calculated new disability weights by use of representative community surveys and an internet-based survey. We combined estimates of dependence with disability weights to calculate prevalent YLDs, YLLs, and DALYs, and estimated YLDs, YLLs, and DALYs attributable to drug use as a risk factor for other health outcomes. FINDINGS Illicit drug dependence directly accounted for 20·0 million DALYs (95% UI 15·3-25·4 million) in 2010, accounting for 0·8% (0·6-1·0) of global all-cause DALYs. Worldwide, more people were dependent on opioids and amphetamines than other drugs. Opioid dependence was the largest contributor to the direct burden of DALYs (9·2 million, 95% UI 7·1-11·4). The proportion of all-cause DALYs attributed to drug dependence was 20 times higher in some regions than others, with an increased proportion of burden in countries with the highest incomes. Injecting drug use as a risk factor for HIV accounted for 2·1 million DALYs (95% UI 1·1-3·6 million) and as a risk factor for hepatitis C accounted for 502,000 DALYs (286,000-891,000). Suicide as a risk of amphetamine dependence accounted for 854,000 DALYs (291,000-1,791,000), as a risk of opioid dependence for 671,000 DALYs (329,000-1,730,000), and as a risk of cocaine dependence for 324,000 DALYs (109,000-682,000). Countries with the highest rate of burden (>650 DALYs per 100,000 population) included the USA, UK, Russia, and Australia. INTERPRETATION Illicit drug use is an important contributor to the global burden of disease. Efficient strategies to reduce disease burden of opioid dependence and injecting drug use, such as delivery of opioid substitution treatment and needle and syringe programmes, are needed to reduce this burden at a population scale. FUNDING Australian National Health and Medical Research Council, Australian Government Department of Health and Ageing, Bill & Melinda Gates Foundation.

Global variation in the prevalence and incidence of major depressive disorder: a systematic review of the epidemiological literature

BACKGROUND Summarizing the epidemiology of major depressive disorder (MDD) at a global level is complicated by significant heterogeneity in the data. The aim of this study is to present a global summary of the prevalence and incidence of MDD, accounting for sources of bias, and dealing with heterogeneity. Findings are informing MDD burden quantification in the Global Burden of Disease (GBD) 2010 Study. METHOD A systematic review of prevalence and incidence of MDD was undertaken. Electronic databases Medline, PsycINFO and EMBASE were searched. Community-representative studies adhering to suitable diagnostic nomenclature were included. A meta-regression was conducted to explore sources of heterogeneity in prevalence and guide the stratification of data in a meta-analysis. RESULTS The literature search identified 116 prevalence and four incidence studies. Prevalence period, sex, year of study, depression subtype, survey instrument, age and region were significant determinants of prevalence, explaining 57.7% of the variability between studies. The global point prevalence of MDD, adjusting for methodological differences, was 4.7% (4.4-5.0%). The pooled annual incidence was 3.0% (2.4-3.8%), clearly at odds with the pooled prevalence estimates and the previously reported average duration of 30 weeks for an episode of MDD. CONCLUSIONS Our findings provide a comprehensive and up-to-date profile of the prevalence of MDD globally. Region and study methodology influenced the prevalence of MDD. This needs to be considered in the GBD 2010 study and in investigations into the ecological determinants of MDD. Good-quality estimates from low-/middle-income countries were sparse. More accurate data on incidence are also required.

The Global Burden of Mental, Neurological and Substance Use Disorders: An Analysis from the Global Burden of Disease Study 2010

Background The Global Burden of Disease Study 2010 (GBD 2010), estimated that a substantial proportion of the world’s disease burden came from mental, neurological and substance use disorders. In this paper, we used GBD 2010 data to investigate time, year, region and age specific trends in burden due to mental, neurological and substance use disorders. Method For each disorder, prevalence data were assembled from systematic literature reviews. DisMod-MR, a Bayesian meta-regression tool, was used to model prevalence by country, region, age, sex and year. Prevalence data were combined with disability weights derived from survey data to estimate years lived with disability (YLDs). Years lost to premature mortality (YLLs) were estimated by multiplying deaths occurring as a result of a given disorder by the reference standard life expectancy at the age death occurred. Disability-adjusted life years (DALYs) were computed as the sum of YLDs and YLLs. Results In 2010, mental, neurological and substance use disorders accounted for 10.4% of global DALYs, 2.3% of global YLLs and, 28.5% of global YLDs, making them the leading cause of YLDs. Mental disorders accounted for the largest proportion of DALYs (56.7%), followed by neurological disorders (28.6%) and substance use disorders (14.7%). DALYs peaked in early adulthood for mental and substance use disorders but were more consistent across age for neurological disorders. Females accounted for more DALYs in all mental and neurological disorders, except for mental disorders occurring in childhood, schizophrenia, substance use disorders, Parkinson’s disease and epilepsy where males accounted for more DALYs. Overall DALYs were highest in Eastern Europe/Central Asia and lowest in East Asia/the Pacific. Conclusion Mental, neurological and substance use disorders contribute to a significant proportion of disease burden. Health systems can respond by implementing established, cost effective interventions, or by supporting the research necessary to develop better prevention and treatment options.

Global prevalence of anxiety disorders: a systematic review and meta-regression

BACKGROUND The literature describing the global prevalence of anxiety disorders is highly variable. A systematic review and meta-regression were undertaken to estimate the prevalence of anxiety disorders and to identify factors that may influence these estimates. The findings will inform the new Global Burden of Disease study. Method A systematic review identified prevalence studies of anxiety disorders published between 1980 and 2009. Electronic databases, reference lists, review articles and monographs were searched and experts then contacted to identify missing studies. Substantive and methodological factors associated with inter-study variability were identified through meta-regression analyses and the global prevalence of anxiety disorders was calculated adjusting for study methodology. RESULTS The prevalence of anxiety disorders was obtained from 87 studies across 44 countries. Estimates of current prevalence ranged between 0.9% and 28.3% and past-year prevalence between 2.4% and 29.8%. Substantive factors including gender, age, culture, conflict and economic status, and urbanicity accounted for the greatest proportion of variability. Methodological factors in the final multivariate model (prevalence period, number of disorders and diagnostic instrument) explained an additional 13% of variance between studies. The global current prevalence of anxiety disorders adjusted for methodological differences was 7.3% (4.8-10.9%) and ranged from 5.3% (3.5-8.1%) in African cultures to 10.4% (7.0-15.5%) in Euro/Anglo cultures. CONCLUSIONS Anxiety disorders are common and the substantive and methodological factors identified here explain much of the variability in prevalence estimates. Specific attention should be paid to cultural differences in responses to survey instruments for anxiety disorders.

Suicide in developing countries (2): risk factors.

The majority of studies on risk factors for suicide have been conducted in developed countries, and less work has been done to systematically profile risk factors in developing countries. The current paper presents a selective review of sociodemographic, clinical, and environmental/situational risk factors in developing countries. Taken together, the evidence suggests that the profiles of risk factors in developing countries demonstrate some differences from those in developed countries. In some developing countries, at least, being female, living in a rural area, and holding religious beliefs that sanction suicide may be of more relevance to suicide risk than these factors are in developed countries. Conversely, being single or having a history of mental illness may be of less relevance. Risk factors that appear to be universal include youth or old age, low socioeconomic standing, substance use, and previous suicide attempts. Recent stressful life events play a role in both developing and developed countries, although their nature may differ (e.g., social change may have more of an influence in the former). Likewise, access to means heightens risk in both, but the specific means may vary (e.g., access to pesticides is of more relevance in developing countries). These findings have clear implications for suicide prevention, suggesting that preventive efforts that have shown promise in developed countries may need to be tailored differently to address the risk factor profile of developing countries.

Suicide in Developing Countries (1)

OBJECTIVE Suicide is a global public health problem, but relatively little epidemiological investigation of the phenomenon has occurred in developing countries. This paper aims to (1) examine the availability of rate data in developing countries, (2) provide a description of the frequency and distribution of suicide in those countries for which data are available, and (3) explore the relationship between country-level socioeconomic factors and suicide rates. It is accompanied by two companion papers that consider risk factors and preventive efforts associated with suicide in developing countries, respectively. METHOD Using World Health Organization data, we calculated the average annual male, female, and total suicide rates during the 1990s for individual countries and regions (classified according to the Human Development Index [HDI]), and examined the association between a range of socioeconomic indicators and suicide rates. RESULTS For reasons of data availability, we concentrated on medium HDI countries. Suicide rates in these countries were variable. They were generally comparable with those in high HDI countries from the same region, with some exceptions. High education levels, high telephone density, and high per capita levels of cigarette consumption were associated with high suicide rates; high levels of inequality were associated with low suicide rates. CONCLUSION Epidemiological investigations of this kind have the potential to inform suicide prevention efforts in developing countries, and should be encouraged.

Addressing the burden of mental, neurological, and substance use disorders: key messages from Disease Control Priorities, 3rd edition

The burden of mental, neurological, and substance use (MNS) disorders increased by 41% between 1990 and 2010 and now accounts for one in every 10 lost years of health globally. This sobering statistic does not take into account the substantial excess mortality associated with these disorders or the social and economic consequences of MNS disorders on affected persons, their caregivers, and society. A wide variety of effective interventions, including drugs, psychological treatments, and social interventions, can prevent and treat MNS disorders. At the population-level platform of service delivery, best practices include legislative measures to restrict access to means of self-harm or suicide and to reduce the availability of and demand for alcohol. At the community-level platform, best practices include life-skills training in schools to build social and emotional competencies. At the health-care-level platform, we identify three delivery channels. Two of these delivery channels are especially relevant from a public health perspective: self-management (eg, web-based psychological therapy for depression and anxiety disorders) and primary care and community outreach (eg, non-specialist health worker delivering psychological and pharmacological management of selected disorders). The third delivery channel, hospital care, which includes specialist services for MNS disorders and first-level hospitals providing other types of services (such as general medicine, HIV, or paediatric care), play an important part for a smaller proportion of cases with severe, refractory, or emergency presentations and for the integration of mental health care in other health-care channels, respectively. The costs of providing a significantly scaled up package of specified cost-effective interventions for prioritised MNS disorders in low-income and lower-middle-income countries is estimated at US