Estimating the number of adults with severe and persistent mental illness who have complex, multi-agency needs

A population health approach to mental health service planning requires estimates that align interventions with the needs of people with mental illness. The primary objective was to estimate the number of people in Australia living with severe and persistent mental illness who have complex, multi-agency needs. The secondary objective was to describe the possible service needs of individuals with severe mental illness.

We disaggregated the estimated 12-month prevalence of adults with severe mental illness into needs-based sub-groups, using multiple data sources. Possible service needs of 1825 adults with psychotic disorders and 334 adults with severe past-year affective and/or anxiety disorders were described using data from the 2010 Survey of High Impact Psychosis and 2007 National Survey of Mental Health and Wellbeing, respectively.

Using best available data, we estimated that 3.3% of adults experience a severe mental illness each year, of whom one-third (1.1% of adults) experience a persistent mental illness that requires ongoing services to address residual disability. Among those with severe and persistent mental illness, one-third of adults (0.4% or 59,000 adults in 2015) have complex needs requiring multi-agency support to maximise their health, housing, social participation and personal functioning. Survey of High Impact Psychosis data indicated that among adults with psychotic disorders, use of accommodation (40%), non-government (30%) services and receipt of income support (85%) services were common, as were possible needs for support with socialising, personal care and employment. National Survey of Mental Health and Wellbeing data indicated that among individuals with severe affective and anxiety disorders, receipt of income support (37%) was common (information on accommodation and non-government support services was not available), as were possible needs for financial management and employment support.

Agreed indicators of complex, multi-agency needs are required to refine these estimates. Closer alignment of information collected about possible service needs across epidemiological surveys is needed.