Defining a Mental Illness Cohort

Project Rationale

Well established that mental illness is associated with poor physical health and chronic diseases possibly related to high levels of risk factors such as smoking, physical inactivity, poor diet and alcohol consumption. There is also evidence to suggest that having a mental illness may be related to poorer management of chronic diseases.

Project Aim/s

1. Investigate an appropriate definition to identify a mental health cohort within the Central and Eastern Sydney Area (CES) area of Sydney who are participants within the 45 and Up Study.
2. Investigate the feasibility of potential areas for further research on health service utilisation within this group

Project Design and Method

Scope the feasibility of identifying a mental illness cohort using CES residents in the 45 and Up Study linked to administrative health datasets for five years from the 45 and Up Study participant recruitment date (2006-2009).

MBS related mental health claims include any MBS subsidised mental health services such as: Psychiatrists, GP mental health services, psychologists. PBS related mental health claims includes any claims made for medicines within the broad categories of psycholeptics (including hypnotics, anti-psychotics, anxiolytics) and psychoanaleptics (antidepressants, psychostimulants). Hospitalisations were included if they had a diagnostic code from ICD10 Chapter 5 “Mental and  Behavioural Disorders” (F00-F99) anywhere within the principle or associated diagnosis fields.

Outcomes/Outputs

Using only hospitalisation data, 6% of the CES cohort were identified as having a mental illness, compared to 17% using MBS data only, 26% PBS data only, 35% using both the MBS and PBS data and 36% using all of the data sources.

Crude mortality was 58% in those identified in the hospitalisation data, 27% based on the PBS data,10% using MBS data, 21% using the MBS and PBS data and 23% based on all combined sources.