National mental health report 2013

1.2 The magnitude of the problem: indicators of mental illness in Australia

Page last updated: 2013

In order to examine the achievements of the National Mental Health Strategy, it is necessary to gauge the number of people affected by mental illness in the Australian population, and to understand how mental illness affects their lives.

When the National Mental Health Strategy began, no information was available about the extent and impact of mental illness in Australia, so, in the late 1990s, a program of population surveying was commenced. Known collectively as the National Survey of Mental Health and Wellbeing, it comprised three cross‑sectional surveys. The first took place in 1997 and investigated the prevalence and impact of common mental disorders (depression, anxiety and substance use disorders) in adults.4 The second survey, also conducted in 1997 and targeted at adults, focused on the less common mental illnesses (in particular, psychotic disorders).5 Because neither of the first two surveys could shed light on young people’s mental health, the third study was commissioned in 1998 to capture information about the mental health of children and adolescents.6 The two surveys of adults were repeated in 2007 and 2010, respectively.7,8,9 A new survey of children and adolescents has been commissioned and will be conducted in 2013. More detail about the scope of these studies is provided in Table 1 National Survey of Mental Health and Wellbeing: Epidemiological studies commissioned to measure the extent and impact of mental illness in Australia. The following text draws on data from the most recent surveys only.

The 2007 survey of the adult population found that one in five (20%) – 3.2 million individuals – experienced one of the common mental disorders in the preceding year. Fourteen per cent experienced anxiety disorders, 6% mood disorders, and 5% substance use disorders. One quarter experienced two or more of these conditions in the year of interest. Prevalence was highest among those aged 16‑24 (26%) and declined with age, and two thirds of those with depression and/or anxiety disorders had experienced their first episode before the age of 21. This highlights the need for an emphasis on early intervention services that target younger people.

Turning to lower prevalence disorders, the 2010 Survey of People Living with Psychotic Illness found that 0.5% of the adult population had been treated for a psychotic disorder in the previous year. This equates to 64,000 people, almost half of whom had schizophrenia. Two thirds of these people experienced their initial episode before they turned 25, and many of them had experienced disabling, unremitting symptoms since the onset of their illness.7 Psychotic illnesses are the focus of many state and territory mental health services and account for the majority of resources devoted to specialist mental health care in Australia.

The above adult surveys showed that many people with mental illness experience symptoms quite early in their lives. The 1998 child and adolescent survey further emphasised the importance of the early years, showing that 14% of those aged 4‑17 were affected by a clinically significant mental health problem. This amounted to about 500,000 individuals, including 93,000 with anxiety or depression, 200,000 with aggressive behaviours, and 93,000 with attention deficit disorders. As noted above, these figures will be updated by the 2013 survey data. Top of page

Prevalence estimates only provide part of the picture and need to be complemented by an understanding of the extent to which mental illness contributes to overall ill health. Figures from the 2003 World Health Organization’s Global Burden of Disease (GBD) study provide some insights here. The GBD study measured the burden of all diseases using a common metric that is based on years of life lost due to premature mortality and years of life lived in less than full health (morbidity). Most of the burden of mental disorders is associated with morbidity, not mortality. Mental disorders accounted for 24% of the total burden of non‑fatal disease and injury in Australia in 2003.10 The recently released figures from the 2010 GBD study present a similar picture.11

Mental illness impacts on people’s lives at different levels of severity. Various modelling exercises have been conducted that combine data from the Australian prevalence studies with data from other sources, including the GBD study, in order to inform service system planning (see Figure 1).12 These analyses suggest that an estimated 2‑3% of Australians – around 600,000 people – have severe disorders, as judged by diagnosis, intensity and duration of symptoms, and degree of disability. This group is not confined to those with psychotic disorders who in fact represent only about one third of those with severe mental illness; it also includes people with severe and disabling forms of depression and anxiety. Another 4‑6% of the population (approximately 1 million people) have moderate disorders, and a further 9‑12% (approximately 2 million people) have mild disorders.

Taken together, the combined estimates of prevalence, disability and severity provide guidance for planning services, allocating resources and evaluating the overall effectiveness of the National Mental Health Strategy. They show that mental illness is a common problem in the Australian community. They also suggest, however, that individuals experience mental illness in different ways. Some people have severe and debilitating disorders, whereas others have mild or moderate conditions. Top of page

The corollary of this is that there is not a one size fits all solution to mental health care. Some people have extensive and ongoing needs for services whereas others may only need care occasionally or for a brief period, or may not need care at all. The 2007 National Survey of Mental Health and Wellbeing of adults showed that only 35% of those who met criteria for a mental disorder made use of services for mental health problems, but that this varied by level of severity (64% of those with severe disorders received services, 39% of those with moderate disorders did so, and 17% of those with mild disorders did so).8 13 However, 86% of those who did not receive mental health care indicated that they had no need for any of the kinds of services that are typically offered (for example, information, medication, talking therapy, social intervention and skills training).14 Ensuring that appropriate, high quality services are available to those who need them, when they need them, has been a consistent goal of the National Mental Health Strategy since its inception.

The National Mental Health Strategy aims to reduce both the prevalence and severity of mental illness. This is embodied in the Strategy’s population health approach, which recognises that the determinants of mental health status comprise a range of psychosocial and environmental factors (including, for example, income, employment, education and access to community resources), and encompasses the entire spectrum of interventions from mental health promotion and mental illness prevention through to recovery. A reduction in the prevalence of mental illness may be brought about by preventive efforts to stop an illness occurring in the first place, or by increasing access to effective treatments to reduce the duration of illness for those who already have symptoms. Reducing the severity of mental illness requires a range of services designed to alleviate the disablement that may be associated with a person’s social, personal and vocational functioning. Top of page

Table 1: National survey of mental health and wellbeing: epidemiological studies commissioned to measure the extent and impact of mental illness in Australia

Table 1 is presented as three tables in this html version. It is a single table in the PDF version.

Survey of adult population

YearTarget group and focusSample sizeRecruitment methodData collection methodPrevalence estimates
1997Adults (aged 18+), common mental disorders (depression, anxiety and substance use)
10,641
Recruited through householdsStructured diagnostic interviewsOne year prevalence (community): 17.7%
2007Adults (aged 16-85), common mental disorders (particularly depression, anxiety and substance use disorders)
8,841
Recruited through householdsStructured diagnostic interviewsOne year prevalence (community): 20.0%
Lifetime prevalence (community): 45.0%

Survey of people living with psychotic illness

YearTarget group and focusSample sizeRecruitment methodData collection methodPrevalence estimates
1997Adults (aged 18-64), psychotic disorders
980
Recruited through specialist mental health services, GPs and private psychiatristsCensus, interviews, information from service providersOne month prevalence (treated): 0.4-0.7%
2010Adults (aged 18-64), psychotic disorders
1,825
Recruited through specialist mental health services and non-government organisationsCensus, interviews, information from GPs and other service providersOne month prevalence (treated): 0.3%
One year prevalence (treated): 0.5%

Survey of children and adolescents

YearTarget group and focusSample sizeRecruitment methodData collection methodPrevalence estimates
1998Children and adolescents (aged 4-17), common mental disorders
4,509
Recruited through householdsInterviewsPoint prevalence (community): 14.1%
Survey in the field May to December 2013Children and adolescents (aged 4-17), common mental disorders
6,300
Recruited through householdsStructured diagnostic interviewsResults due for publication late 2014
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Figure 1: 12 month prevalence estimates of mental illness in the population by severity level, based on diagnosis, disability and chronicity

Refer to the following text for a text equivalent of Figure 1: 12 month prevalence estimates of mental illness in the population by severity level, based on diagnosis, disability and chronicity

Text version of figure 1

This diagram divides the population according to severity of illness:
  • 80% of the general population has no current mental illness. Note that, in addition to the groups with current mild, moderate and severe mental illness, a further 25% of the population will experience a mental illness at some point in their lives.
  • 9-12% of the population has mild mental illness. This is approximately 2 million Australians.
  • 4-6% of the population has moderate mental illness. This is approximately 1 million Australians.
  • 2-3% of the population has severe mental illness. This is approximately 600,000 Australians. Top of page