Research projects

Early detection and treatment of depression in mildly intellectually disabled adults

Principal Researchers

Dr Jane McGillivray¹ and Professor Marita McCabe¹


¹ School of Psychology, Deakin University



Award Type

beyondblue Victorian Centre of Excellence

Project completion year


Project brief

The existence of depression and other mood disorders among people with intellectual disability (ID) is well accepted and there are indications that their risk for developing depression may be greater than the general population.  Despite this recognition, considerable gaps exist in our knowledge regarding early detection and treatment of depression in people with ID. 

This project involved two linked studies. The aim of Study 1 was to determine the presentation and risk factors for depression in a sample of community-based adults with mild/moderate ID.  One hundred and fifty one adults with ID were recruited from vocational and supported employment services.  A semi-structured interview format assessed participants for mood and risk factors.  Comparisons were undertaken between individuals with symptoms of depression and those without on: levels of social support; occurrence of recently disruptive life-events; automatic thoughts; and social comparison and self-esteem.

The aim of Study 2 was to develop and evaluate the effectiveness of a group cognitive behavioural therapy (CBT) program designed to reduce depression in this population.   34 people took part in the intervention program.  They had already participated in study 1 and had displayed symptoms on the Beck Inventory indicating depression or risk for depression. Fifteen participants (matched on depression score, age and gender) comprised a waiting list control group, who subsequently undertook the program.   The program was delivered in groups of 3 - 5 individuals in 5 x 2 hour sessions.  Participants were taught how to self-monitor their moods and thoughts, and were trained to self-reinforce adaptive behaviours. Emphasis was placed on reshaping cognitive distortions and developing a more positive interpretation of events. Techniques of modelling, role-play and structured-feedback were used, and homework activities were included.  The group format enabled participants to practice skills with peers in a social environment where trust and respect for others could be developed.

Key Findings

Thirty nine percent of participants in Study 1 evidenced symptoms of depression (2 severe, 14 moderate, 43 mild). Sadness, self-criticism, loss of energy, crying, and tiredness appeared be the most frequent indicators of depression or risk for depression.  A significant difference was found between individuals with and without symptoms of depression on levels of automatic negative thoughts, downward social comparison and self-esteem.  Automatic negative thoughts, quality and frequency of social support, self-esteem, and disruptive life events significantly predicted depression scores in people with mild/moderate ID.

After completion of the intervention program, there was a significant reduction in depression scores and frequency of negative automatic thoughts.  The extent of positive self-appraisal in comparison to others was higher for those who had completed the program, than those on the waiting list. The impact of the intervention was sustained at a 3 month follow-up.  

Implications for Policy and Practice

This study confirmed that depression is a common mental health problem among people with ID.  Although factors may vary across individuals, some of the most important factors to consider in determining what might lead to the development of depression in this population have been identified.  It is recommended that people with mild/moderate ID are routinely screened for the presence of depression symptoms and for the factors that contribute to these symptoms.

The CBT program implemented in the current study was effective in reducing depressive symptoms and improving how people with mild/moderate ID feel about themselves as they compare themselves to others.  These findings are extremely positive, and indicate that CBT treatment programs be made available to individuals with mild/moderate ID who display symptoms of depression or who are at risk for depression.   It is also recommended that primary health care providers receive training in the detection of depression symptoms and in CBT treatment interventions that are tailored for people with mild/moderate ID. 

Future Directions 

This research has served as the basis for a further beyondblue funded project in which our treatment program (“Think happy, Feel happy, Be happy”) has been refined and manualised so that it can be administered by trained staff in agencies providing services to individuals with mild ID.  Initial findings are again positive.  There remains a need for our CBT program to be evaluated across a range of regional and metropolitan disability agencies and with the opportunity for evaluation of effectiveness over a period of at least 12 months. 

About the Researcher

Jane McGillivray is a Senior Lecturer in the School of Psychology at Deakin University and has extensive clinical and research experience in the mental health and well-being of people with intellectual disability.  She has been recognised in this field through her successive statutory appointments as psychologist member to the Intellectual Disability Review Panel and as co-recipient of the Australian Society for the Study of Intellectual Disability 2001 National Research Prize. The focus of her recent publications includes the pharmacological management of challenging behaviours and the development of interventions for depression in people with intellectual disability.

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