In this study, we will undertake detailed analyses of the largest cross-national epidemiologic study of mental and substance use disorders ever conducted. The WHO World Mental Health Survey (WMHS) initiative is a massive, unique endeavour. It contains data on around 160,000 participants from 31 countries. Samples are epidemiological surveys in: 16 countries classified by the World Bank as high income (Argentina, Australia, Belgium, France, Germany, Israel, Italy, Japan, Netherlands, New Zealand, Northern Ireland, Poland, Portugal, Saudi Arabia, Spain, United States); 7 classified as upper-middle income (São Paulo in Brazil, Bulgaria, Medellin (Columbia), Lebanon, Mexico, Romania, South Africa); and 8 classified as lower-middle income (Beijing, Shanghai and Shenzhen in the Peoples’ Republic of China, Columbia, Iraq, Nigeria, Peru, Ukraine). These countries vary substantially in many other ways including culture, religiosity and gender roles.
Substance Use Workgroup:
Ronald Kessler, PhD
Harvard University School of Medicine, United States
Meyer Glantz, PhD
National Institute on Drug Abuse, United States
Maria Elena Medina-Mora, PhD
National Institute of Psychiatry, Mexico
Dan Stein, MD
University of Stellenbosch, South Africa
Jacek Moskalewicz, PhD
Institute of Psychiatry and Neurology, Poland
Elie Karam, MD
St George Hospital University Medical Centre, Lebanon
Laura Andrade, MD, PhD
University of Sao Paulo, Brazil
Yolanda Torres de Galvis, MPH
Centro de Excelencia en Investigación en Salud Mental, Universidad CES, Colombia
J. Elisabeth Wells, PhD
Department of Public Health and General Practice, University of Otago, New Zealand
Alcohol and illicit drug use are among the biggest risk factors for burden of disease. They caused around 5 million deaths globally in 2010, and were responsible for more than 161 million years of life lost due to disability or premature death, equating to 5% of total global health burden. In Australia, 88% of people have consumed alcohol, and 35% illicit drugs. One in four adults - almost 4 million Australians - have a history of harmful use or dependence upon these substances (“substance use disorders” (SUDs) as defined by the World Health Organization (WHO)). The impact of such widespread exposure to substance use is immense. In 2004/5 alone, the social costs to Australian society of alcohol and illicit drugs were estimated at $24.6 billion.
Despite this, there are substantial gaps in epidemiological data on this issue. No study has charted the entire natural history of substance use and substance use disorders across the life-span, including critical transitions such as the onset of substance use, the speed of transition from use to disorder, and the probability of remission from SUDs. Prospective studies that examine prognosis of SUDs have typically been based on people seeking treatment for their substance use, or entering the criminal justice system. The natural history of substance use and SUD in these people probably differs from those who do not come to the attention of treatment services or police. There has also been little examination of whether the natural history of substance use and SUDs is consistent across countries and cultures, since most studies have been in relatively homogenous, high income countries. Finally, although work has examined which risk factors individually increase the probability of experiencing SUDs, there has been little work examining an optimal composite risk score to predict those at greatest risk of SUDs. Such scores will guide early intervention efforts.
We aim to:
- Estimate the incidence, prevalence, persistence and remission of alcohol and illicit substance use (cannabis, cocaine, amphetamines and opioids) and use disorders across 31 countries;
- Examine patterns and predictors of transitions from use to symptom onset, from symptom onset to substance abuse and dependence, and transition to remission, considering country-level variation;
- Using novel “data mining” methods, develop an algorithm to predict substance users at highest risk of developing SUDs, and further identify subgroups within those highest-risk groups who may differ in clinically meaningful ways, informing secondary prevention of SUDs.
A meeting of all WMHS collaborators was held in Boston in July 2016. Prof Degenhardt attended this meeting and Prof Degenhardt presented preliminary analysis showing cross-national prevalence alcohol use and alcohol use disorders. The substance use workgroup met on several occasions during this meeting to discuss these results and agree to the most important priorities and areas of research in substance use using the WMHS data. Based on feedback from this meeting a series of tasks and paper ideas were mapped out. Weekly international teleconferences were held to progress this work program. A small team from within the substance use workgroup attended these meetings and provided feedback on analysis and papers.
In November 2016, Miss Bharat, a new analyst to the project, also undertook training in the use of the WMHS data at Harvard Medical School with the aim of extending the analysis cross-nationally.
Dr Lago carried out imputation for several key variables in the substance use component of the WMHS. A paper describing this methodology is under review. A paper on the concordance between ICD-11 and DSM-5 in Australian national survey data was published. Several other papers are under review from this project. Data analysis investigating the predictors of transition between alcohol and cannabis use stages for the Australian population is complete and a paper describing the results is close to submission.
Slade, T., Chiu, W.T., Glantz, M., Kessler, R.C., Lago, L., Sampson, N., Al-Hamzawi, A., Florescu, S., Moskalewicz, J., Murphy, S., Navarro-Mateu, F., Torres de Galvis, Y., Viana, M.C., Xavier, M., Degenhardt, L. (epub 2016). A Cross-National Examination of Differences in Classification of Lifetime Alcohol Use Disorder Between DSM-IV and DSM-5: Findings from the World Mental Health Survey. Alcoholism Clinical and Experimental Research, 40(8), 1728-36.
- Thornicroft, G., Chatterji, S., Evans-Lacko, S., Gruber, M., Sampson, N., Aguilar-Gaxiola, S., Al-Hamzawi, A., Alonso, J., Andrade, L., Borges, G., Bruffaerts, R., Bunting, B., Miguel Caldas de Almeida, J., Florescu, S., de Girolamo, G., Gureje, O., Maria Haro, J., He, Y., Hinkov, H., Karam, E., Kawakami, N., Lee, S., Navarro-Mateu, F., Piazza, M., Posada-Villa, J., Torres de Galvis, Y., Kessler, R., on behalf of the WMHS study collaborators (in press accepted September 1st 2016). Under-treatment of people with major depressive disorder in 22 countries. British Journal of Psychiatry.
- Lago, L., Bruno, R. & Degenhardt, L. (2016). Concordance between ICD-11 and DSM-5 definitions of alcohol and cannabis use disorders: A population study. The Lancet Psychiatry, 3, 673-684.