Epidemiology

Epidemiology

Stream Description

image - EpidemiologyEpidemiological studies of mental health and substance use disorders are vital to understanding the size and nature of the health challenges posed by these disorders. Our epidemiology stream aims to carry out epidemiological studies, both cross-sectional and longitudinal, examining the prevalence, correlates and natural history of mental health and substance use disorders. We also aim to carry out studies to refine and improve the ways in which mental health and substance use disorders are diagnosed and classified. In order to understand the distribution and impact of mental health and substance use disorders we undertake secondary analysis of existing epidemiological data sets, such as the Australian National Surveys of Mental Health and Wellbeing. Using innovative data analytic techniques we answer research questions such as:

  1.  What is the prevalence of alcohol use disorders in the general population and what sub-groups of the general population are at most risk of experiencing an alcohol use disorder?
  2. How has the prevalence of risky alcohol use and alcohol use disorders changed over time? How has the gender gap in risky alcohol use changed in more recent decades?
  3. What is the relationship between pre-existing mental disorders and the subsequent development of substance use disorders? How many people with a substance use disorder go on to develop a mental disorder
  4. What is the extent of the delay between the onset of a substance use disorder and the onset of treatment seeking? Does this delay differ depending on different demographic characteristic?
  5. Are the proposed changes to the DSM-IV diagnosis of alcohol use disorder valid?

Ongoing Projects

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2007 National Survey of Mental Health and Wellbeing (NSMHWB)

Funding Body: Australian Government Department of Health and Ageing
Description:

The 2007 National Survey of Mental Health and Wellbeing was conducted to provide updated evidence on the prevalence of mental illness in the Australian population, the amount of associated disability, comorbidity of mental disorders and comorbidity of mental disorders and chronic physical conditions, and the use of health services by people with mental disorders.The 2007 NSMHWB is a general household survey of the adult population aged 16-85 years, which was conducted by the Australian Bureau of Statistics from August to December 2007. This project aims to disseminate the findings of the 2007 NSMHWB regarding the prevalence and impact of mental and substance use disorders.

Project Contacts: A/Prof Tim Slade
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A dimensional-spectrum model of mental disorders: developing new assessments to improve the diagnostic validity of multiple mental disorders

Funding Body: NHMRC
Description:

The current program of research seeks to investigate new and emerging statistical models to develop accurate and efficient instruments that measure the latent relationship between internalising (eg. depression, anxiety), externalising (eg. substance use, anti-social and conduct disorder) and thought disorders (eg. psychosis).

A growing body of empirical evidence has questioned the validity of categorical diagnostic instruments. Converging lines of evidence suggest that models of psychopathology that measure multiple disorders through the use of broad dimensional spectra offer a significant improvement to psychiatric research and clinical practice. This model is commonly referred to as a dimensional-spectrum model. In order to facilitate the use of dimensional models to measure the broad spectra of psychopathology there is a growing need for new assessment tools that measure the dimensionality of psychiatric disorders. Previously, dimensional instruments for individual disorders have been developed however no study has examined the possibility of constructing a tool that measures the complex latent relationship between putatively distinct disorders using a dimensional-spectrum model. Advances in measurement theory, particularly multidimensional Item Response Theory (IRT), offer innovative ways to measure broad dimensional constructs. These methods can be utilised for the development of efficient and accurate diagnostic tools through the use of computerised adaptive testing.

The current research program aims to develop and test an innovative and novel approach for measuring psychiatric disorders in community and clinical populations using a dimensional-spectrum model as the guiding theoretical framework.

Project Contacts: Dr Matthew Sunderland

How do we translate Research Investments into Clinical Outcomes in Australian Mental Health Services?

Funding Body: Macquarie University Research Development Grant
Description:

Whilst there is growing evidence about the barriers to evidence-based practice in mental health treatment, we understand little about what information clinicians actually use, or their ongoing information needs. This project aims to broaden the typical focus on individual professions and barriers to implementation, and develop an understanding of the information needs of all mental health clinicians in Australia to optimise the dissemination of research into clinical practice.

Project Contacts: Dr Erica Crome
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The Radar Project: identifying early warning signals on the pathways to alcohol use disorder

Dr Wendy Swift Professor Richard Mattick
Funding Body: NHMRC
Description:

Globally, harmful alcohol use continues to be a major modifiable contributor to the burden of disease. In 2004/5, alcohol accounted for 27% (=$15.3 billion) of the Australian social costs of drug abuse, with alcohol use disorder (AUD), defined as a cluster of cognitive, behavioural and physiological symptoms indicating continued alcohol use despite significant problems, representing the most costly alcohol-related harm. Initiation of alcohol use is a rite of passage for many adolescents yet an alarming number drink at levels that put them at risk of harm. Such risky drinking patterns are strongly associated with the development of AUD and can trigger a cascade of lifelong adverse outcomes, such as mental disorders, suicide, other illicit drug use and antisocial behaviour as well as early onset of heart disease, stroke and cancer.

Australian and international adult population data indicate that the peak age of onset of AUD is 18 years, thus a deeper understanding of the adolescent experience is vital if we are to identify modifiable risk factors and intervene early in the developmental course of this disabling disorder. More broadly, despite spectacular improvements in the health of young children, indicators of adolescent health, including violence and injury associated with alcohol use, remain unchanged over the past 50 years. Through initiatives such as the recently established Lancet Commission on Adolescent Health and Wellbeing adolescents are now central in efforts to improve global health.

The proposed study responds to an urgent call for high quality, long-term prospective cohort studies to better understand the health burden of adolescent drinking. Critical unanswered questions include: How soon after drinking initiation do AUD symptoms begin to emerge? Which symptoms come first? Do the symptoms unfold in a predictable pattern? In what ways do the emerging symptoms interact with individual, peer, family and environmental risk factors to predict the transition to disorder?

The aim of the project is to conduct a world-first, intensive, longitudinal study of the developmental course of AUD across adolescence and young adulthood. The overarching hypothesis is that the timing, rate and order of symptom development will account for differences in the risk of developing AUD. The specific objectives are to 1) prospectively measure the presence, age at onset and temporal unfolding of AUD symptoms and 2) determine the individual, peer, family and environmental factors that, in the presence of early symptoms, predict transition to AUD.

Project Contacts: A/Prof Tim Slade

Untangling co-morbidity: substance use and mental health in young Australians

Funding Body: APA and Rotary Health
Description:

This project aims to investigate the co-morbidity (co-occurrence within one individual) of mental health problems and substance use in young Australians. To date the study has utilised large epidemiological datasets to map the developmental sequence of anxiety and mood disorders and first alcohol use in the Australian population. Data is currently being analysed from the control group of  a prevention trial involving over 500 adolescents to examine at when, how and why these problems occur together. Adolescence has been chosen as it is a time when both mental health and substance use problems first emerge.

Project Contacts: Ms Louise Birrell

Completed Projects

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Alcohol use disorders in young adults: "Youthful epidemic" or diagnostic bias?

Prof Bob Kruger
Funding Body: National Health and Medical Research Council
Description:

Epidemiological studies show that 1 in 5 Australians aged 18-24 are diagnosed as having an alcohol use disorder (AUD). However, there is evidence to suggest that young adults may interpret the diagnostic criteria differently to older adults. The current study aimed to validate the alcohol use disorder criteria in younger populations through the use of novel cognitive interviewing techniques. Results showed that while young adults understand some of the AUD diagnostic criteria as intended (e.g. tolerance), other criteria are misinterpreted, resulting in an over-estimation of the prevalence of alcohol use disorders in this age group.

Project Contacts: A/Prof Tim Slade
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Diagnosing major depression in older Australian adults: Is there evidence for age-related bias?

Dr Philip Batterham
Funding Body: National Health and Medical Research Council
Description:

Epidemiological studies have consistently indicated that the prevalence of depression decreases with increasing age. Researchers have debated whether this finding is a real age-dependent decline or an artefact of sampling and assessment. This study seeks to use statistical methods and cognitive interviewing to investigate the potential for age-related bias in the criteria for major depression. The study will make recommendations to improve the diagnostic methods used diagnose and treat major depression in the old age.

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Secondary traumatic stress among alcohol and other drug workers

Dr Claudia Sannibale, Prof Ann Roche
Description:

There is a growing literature documenting the high prevalence of trauma exposure and post traumatic stress disorder (PTSD) among people with alcohol and other drug (AOD) use disorders. Indeed, in this population trauma exposure is almost universal and up to one-third have current PTSD. Studies have shown that individuals who are involved in the assessment and treatment of traumatised clients may be at risk of secondary traumatic stress (STS). STS has been described as particular behaviours, emotions and stress that result from helping or wanting to help traumatised individuals. STS has been referred to as an occupational hazard for those working with trauma survivors, however, limited research has been conducted in the area. To our knowledge only one US study has examined STS among the AOD workforce. They found that 19% of the AOD workers they assessed met criteria for current STS. While STS has been explored among the AOD workforce in the US, the degree to which it is suffered by AOD workers in Australia is unknown. The aims of the study are to address two research questions:

  1. 1) What is the prevalence of secondary traumatic stress (STS) among AOD workers in Australia?
  2. 2) What factors are associated with the presence of STS and its severity (e.g., professional experience and training; a personal history of trauma exposure and PTSD)?
Project Contacts: Ms Philippa Ewer

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