Ambulatory mental health data demonstrates the high needs of people with an intellectual disability: results from the New South Wales intellectual disability and mental health data linkage project.

OBJECTIVE: To investigate the ambulatory mental health service profile of persons with intellectual disability (ID) in a representative sample of New South Wales (NSW).

METHODS: A statistical linkage key was used to link the Disability Services Minimum Data Set (DS-MDS) and a community mental health services dataset (MH-COM) for a representative area of NSW for the period 2005-2010. Linkage was undertaken in four NSW local health districts (LHDs), covering 36.7% of the NSW population. The mental health profiles and service use characteristics of people with an ID were compared to mental health service users without an ID.

RESULTS: Of the 89,262 people in the MH-COM over this 6-year period, 1,459 people (1.6 %) were identified as having an ID. Compared to those without an ID, people with an ID were more likely to have psychotic disorders, developmental disorders and personality disorders, and more than twice as likely to have an 'unknown' diagnosis. Compared to those without an ID, people with an ID were less likely to have depressive disorders, adjustment disorders and other disorders. Service use profiles revealed that people with an ID had 1.6 times more face-to-face contacts, and a total face-to-face contact time which was 2.5 times longer than people without an ID.

CONCLUSIONS: Ambulatory mental health data from NSW indicates that people with an ID receive care for a distinct range of mental disorders, and experience uncertainty regarding their diagnosis. People with an ID have higher service needs which require recognition and the allocation of specific resources. Such data provide a suitable baseline for future evaluation of the impact of ambulatory mental health reforms for people with an ID.