Prevalence, impact and burden of mental health

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Prevalence, impact and burden of mental health (251KB)

Key points

  • Almost half (45%) of the population aged 16–85 will experience a mental illness at some time in their life, with 1 in 5 (20%) having experienced a common mental illness in the previous 12 months.
  • Anxiety disorders (such as social phobia) are the most prevalent type of illness, afflicting 1 in 7 (14%) of the population, followed by Affective disorders (such as depression) (6%), and Substance use disorders (such as alcohol dependence) (5%).
  • Almost 1 in 7 (14%) children and adolescents aged 4–17 years experienced a mental illness in the previous 12 months.
  • 5% or 800,000 people have a severe mental illness, of which 500,000 people have episodic mental illness and 300,000 have persistent mental illness.
  • Mental and substance use disorders were the second largest contributor (24%) of the non-fatal burden of disease in Australia

Prevalence

In the Mental health services in Australia online report, the terms ‘mental illness’ and ‘mental disorder’ are both used to describe a wide spectrum of mental health and behavioural disorders, which can vary in both severity and duration. The most prevalent mental illnesses in Australia are Depression, Anxiety and Substance use disorders (ABS 2008).

A program of surveys, the National Survey of Mental Health and Wellbeing (NSMHWB), began in Australia in the late 1990s. The role of these surveys is to provide evidence on the prevalence of mental illness in the Australian population, the amount of disability associated with mental illness, and the use of health services by people experiencing mental illness. These studies have 3 main components—a population-based survey of adults, a service-based survey of people with psychotic disorders, and a population-based survey of children.

Psychological distress

Another insight into the mental health and wellbeing of Australians is provided by measures of psychological distress. Psychological distress can be described as unpleasant feelings or emotions that affect a person’s level of functioning and interfere with the activities of daily living. This distress can result in having negative views of the environment, others and oneself, and manifest as symptoms of mental illness, including anxiety and depression. Psychological distress is commonly measured using the Kessler 10 (K10) a psychological distress scale based on questions about negative emotional states experienced in the past 30 days (ABS 2012). Someone experiencing psychological distress will not necessarily be experiencing mental illness, although high scores on the Kessler 10 Psychological Distress Scale (K10) are strongly correlated with the presence of depressive or anxious disorders (Andrews and Slade 2001). As it is relatively straightforward to measure, ‘high’ and ‘very high’ levels of psychological distress are often used as a ‘proxy’ for mental illness.

In 2017–18, 13% or 2.4 million Australians aged 18 and over experienced high or very high levels of psychological distress, which is higher compared to 2014–15 (12% or 2.1 million Australians). High or very high levels of psychological distress were more often reported by females than males in 2017–18 (15% and 11% respectively). Of all age groups, young people (aged 18–24) were most likely to experience high or very high levels of psychological distress (15%) (ABS 2019).

In a longitudinal study, COVID-19 Impact Monitoring Survey Program, researchers from the Australian National University found a substantial increase in the levels of psychological distress between February 2017 and April 2020, the equivalent of an increase of 8% to 11% of people reporting a serious mental illness. Increases in psychological distress were seen particularly for young Australian adults, with the proportion of people aged 18–24 experiencing high levels of psychological distress increasing from 14% in 2017 to 22% in April 2020 (Biddle et al. 2020).

Over the course of the pandemic, psychological distress has fluctuated, reaching highs in April 2020, October 2020 and October 2021. As of January 2022, psychological distress remained elevated compared to February 2017 (Biddle & Gray 2022).

Vulnerable groups

It is well recognised that some groups experience higher rates of mental illness and psychological distress than others.

Aboriginal and Torres Strait Islander people

In 2018–19, among the total Indigenous Australian population, an estimated 24% (187,500) reported a mental health or behavioural condition, with a higher rate among females than males (25% compared with 23%, respectively). An estimated 31% reported experiencing high or very high levels of psychological distress in the previous 4 weeks (ABS 2019). More information can be found at Australia’s health 2020 – Indigenous health and wellbeing.

LGBTIQA+ Australians

Lesbian, gay, bisexual, transgender, intersex, queer/questioning and asexual Australians report lower health and wellbeing compared to Australians generally. A survey of LGBTIQ Australians, the Private Lives survey, has been conducted 3 times since 2005. The most recent survey, undertaken in 2020, attracted 6,835 participants. Three fifths (60.5%) report having been diagnosed with depression and almost half (47.2%) with an anxiety disorder, while over half (57.2% ) report experiencing high or very levels of psychological distress within the past 4 weeks. Furthermore, only 58.6% of people who accessed a mainstream medical clinic felt that their sexual orientation was very or extremely respected, and on 37.7% thought that their gender identity was very or extremely respected (Hill et al. 2020). More information can be found at Private Lives 3.

Australians with a disability

Adults with disability generally experience higher psychological distress than those without disability. In 2017–18, it was estimated that 31.7% of adults with disability experienced high or very high psychological distress in the previous week, compared to 8.0% of the population without disability. People with a psychological disability were the most likely to report high or very high psychological distress (765), followed by people with an intellectual disability (60%) (AIHW 2020). More information can be found at People with disability in Australia.

Impact and burden of mental illness

Mental illness affects all Australians either directly or indirectly. Mental illness can vary in severity and be episodic or persistent in nature. One in 5 Australians experience mental illness in any given year, most of which will be mild (15% or an estimated 2.3 million Australians among the 15.3 million Australians) or moderate (7%, or an estimated 1.2 million people). It is estimated that around 5% or 800,000 people have a severe mental illness, of which 500,000 people have episodic mental illness and 300,000 have persistent mental illness (Productivity Commission 2020).

Mental and substance use disorders, such as Depression, Anxiety and Drug use, are important drivers of disability and morbidity. The Australian Burden of Disease Study 2018 examined the health loss due to disease and injury that is not improved by current treatment, rehabilitative and preventative efforts of the health system and society. For Australia, Mental and substance use disorders were estimated to be responsible for 13% of the total burden of disease in 2015, placing it 4th as a broad disease group after Cancer (18%), Musculoskeletal conditions (13%) and Cardiovascular diseases (14%) (AIHW 2021).

In terms of the non-fatal burden of disease, which is a measure of the number of years of ’healthy’ life lost due to living with a disability, Mental and substance use disorders were the 2nd largest contributor (24%) of the non-fatal burden of disease in Australia, behind Musculoskeletal conditions (25%) (AIHW 2021).

There is an association between diagnosis of mental illness and a physical disorder, often referred to as a ‘ comorbidity disorder. From the 2007 NSMHWB of adults, 1 in 8 (12%) of people with a 12-month mental illness also reported a physical condition, with 1 in 20 (5%) reporting 2 or more physical conditions (ABS 2008).

According to the 2010 National Psychosis Survey, people with a psychotic illness also frequently experience poor physical health outcomes and comorbidities. For example, over one-quarter (27%) of survey participants had heart or circulatory conditions and over one-fifth (21%) had diabetes (compared with 16% and 6% respectively in the general population). The prevalence of Diabetes found in the National Survey of People Living with Psychotic Illness is more than 3 times the rate seen in the general population. Other comorbidities included Epilepsy (7% compared with 0.8% in the general population) and Severe headaches/migraines (25% compared with 9% in the general population) (Morgan et al. 2011).