Investigating the Mental Health of People with Intellectual Disability across the Lifespan
Professor Bruce Tonge, Centre for Developmental Psychiatry & Psychology, Monash University.
Professor Stewart Einfeld, Brain and Mind Research Institute, University of Sydney.
Dr Caroline Mohr, Centre for Developmental Psychiatry & Psychology, Monash University.
Mental illness is 2-3 times more prevalent in people with an intellectual disability (ID) than in the general community. Problems related to mental illness in people with ID frequently causes distress to the individual and their carers, exacerbates their disability, adds to the costs of caring by government and private agencies, as well as disrupting the educational and occupational prospects for the individual Unfortunately, mental illness in this population often goes undetected and therefore untreated. One of the greatest obstacles is that instruments used to assess and assist in diagnosis of mental illness in the general community are not suitable for use with individuals with an ID.
The current study emerged from work conducted on the ACAD project, the internationally unique 15 year follow up study that has led to the development and use of the Developmental Behaviour Checklist (DBC) for parents and teachers. The DBC has been translated into 19 languages and is an instrument that is being used within Australia and internationally for the assessment of a broad range of behavioural and emotional disturbances in young people with mild-profound ID.
Due to clinical and research demands, the Chief Investigators developed a new checklist, the Developmental Behavioural Checklist for Adults (DBC-A). This is used to assess behavioural and emotional disturbances in individuals with an ID that are 19 years and over. The DBC-A is a modified version of the DBC-P with robust psychometric properties. Further, distinct groups of items on the DBC-A can indicate the possible presence of a variety of psychiatric disorders such as psychotic illness, mood and anxiety disorders as well as autism.
Although it is rapidly being adopted by clinicians and researchers, and has already been translated into Dutch, Finish, and French, the DBC-A will be a more constructive assessment tool of psychopathology when standard norms are available.
The study aims to comprehensively survey the prevalence and nature of mental illness in a representative population of adults with ID who live in South Australia, and investigate potential risk and resilience factors. The primary aim is to obtain standardisation data for the Developmental Behaviour Checklist for Adults (DBC-A), a checklist designed to assess emotional and behavioural disturbances in adults with ID, however, the study will also enable the investigation of the mental health problems of specific groups, such as the elderly, and indigenous Australians.
Data collection concluded in 2008, with over 1600 questionnaires completed and returned to the project team. Of these returns, 161 are from indigenous participants and 322 from older participants (over 55 years) which are the focus of the two PhD projects. The project has been presented both nationally and internationally in conference presentations. Now that data collection is complete, the analysis of data is underway with a view to producing a new manual for the DBC-A and several research papers for publication in scholarly journals in 2009.
The current project has received funding from the Australian Research Council (ARC) for three years (2005-2008). Additional support and funding is provided by three Industry Partners: The Intellectual Disability Services Council (IDSC),(now Disability SA) Minda Inc and The Department of Education and Children Services (DECS).
Additional funding has also been provided by the APEX Foundation for Research into Intellectual Disability, and the Helen MacPherson Smith Trust.
Deb S, Hare, & L.,Bhaumik, S. (2007). Dementia Screening Questionnaire for Individuals with Intellectual Disabilities. British Journal of Psychiatry, 190, 440-444.
Mohr, C., Tonge, B.T., & Einfeld, S.L. (2005). The development of a new measure for the assessment of psychopathology in adults with intellectual disability. Journal of Intellectual Disability Research, 49 (7), 469-480.
Prasher,V.P., Asim, F., Holder, R (2004). The Adaptive Behaviour Dementia Questionnaire (ABDQ) : Screening Questionnaire for Dementia in Alzheimer’s disease in Adults with Down Syndrome Research. Developmental Disabilities, 25(4), 385-97.
PhD Research Projects
Two PhD research projects have developed in conjunction with the LifeSpan project
One PhD research project focuses on the ageing process and prevalence of psychiatric disorders in older people with ID. Although it is well recognised that people with Down Syndrome are more likely to experience precocious ageing, dementia, and depression than those without Down Syndrome, little is known about the ageing process and prevalence of psychiatric disorders in people with ID arising from causes other than Down Syndrome. Therefore, the objective of this PhD research project is to address this gap in knowledge and assist carers by providing broad based information about the prevalence and nature of psychiatric disorders in older people with ID.
In addition to providing normative data for the DBC-A for this population, other assessment processes and instruments including the Adaptive Behaviour Dementia Questionnaire (V. Prasher et al., 2004) and the Dementia Screening Questionnaire for Individuals with Intellectual Disabilities (DSQIID) (Deb et al., 2007) will be studied. These will be used to consider the usefulness of the DBC-A in screening for dementia in older people with ID and to determine their usefulness in overcoming diagnostic overshadowing in this group.
At the completion of this research, clinicians and carers will have additional information and resources on which to base their support, which will ultimately lead to both increased longevity and improved quality of life for older people with ID.
The second PhD project is investigating the prevalence and characteristics of behavioural and emotional problems in Aboriginal people with ID. The student undertaking this project works closely with local communities of Aboriginal people to develop with them an approach to researching in this area that is collaborative, inclusive and sensitive to the needs of people who live in remote as well as urban communities.