Mental illness comprises a wide range of disorders and varies in its severity. The effect of mental illness can be severe on the individuals and families concerned and its influence is far-reaching for society as a whole. Social problems commonly associated with mental illness include poverty, unemployment or reduced productivity and homelessness. People with mental illness often experience problems such as isolation, discrimination and stigma.

Around 7.3 million Australians aged 16–85 (45% of that age group) will experience a common mental disorder such as depression, anxiety or a substance use disorder in their lifetime, according to the 2007 National Survey of Mental Health and Wellbeing. Estimates from the second National Survey of Psychotic Illness conducted in March 2010 suggest that almost 64,000 people have a psychotic illness and are in contact with public specialised mental health services each year. The second Australian Child and Adolescent Survey of Mental Health and Wellbeing (Young Minds Matter) released in August 2015, estimates that 560,000 child and adolescents aged 4–17 (about 14%) experienced mental health disorders in 2012–13.

The AIHW estimates that around $10.6 billion per annum is spent on mental health-related services in Australia. Services include residential and community services, hospital based services (both inpatient and outpatient), consultation with specialists and general practitioners.

As well as producing Mental health services in Australia and Mental health services–in brief, the AIHW also provides data analytical support to the National Mental Health Commission and participates in various national mental health committees.