High-quality epidemiological research shows children and adolescents with intellectual disability are four times more likely to have diagnosable mental health problems compared to others their age. This mental health inequality clearly needs attention.
Part of the problem is a process called diagnostic overshadowing: symptoms are incorrectly assumed to be related to the child’s disability rather than an underlying mental health issue. This often makes it difficult to identify mental health problems in children with intellectual disability.
After we account for the impact of diagnostic overshadowing through the use of specialised assessment tools, Australian research shows over 40% of children with intellectual disability have mental health problems that may be serious enough to lead to a psychiatric diagnosis.
The importance of early intervention
Birth cohort studies follow the development of groups of children that are representative of the population. Data from such studies in the United Kingdom and Australia show the inequality in mental health between children with intellectual disability and those without emerges early.
By the time children with intellectual disability are three years old, they have more mental health problems than other children. What’s more, the mental health problems in these children and adolescents persist over time.
A 2006 Australian study of over 400 children and adolescents with intellectual disability found only a small reduction in mental health problems over its 14-year follow-up. It seems that once mental health problems emerge, children with intellectual disability are likely to suffer from them for a long time.
But despite the high level of mental health problems in this group of children, access to treatment is poor. Recent UK research on over 600 children with intellectual disability who also have autism, for instance, showed less than a quarter of those with mental health problems had any contact with relevant services in the previous six months.
Similar results have been found in Australia. In the Australian study mentioned above, researchers found only 10% of their sample had received specialised mental health treatment from an expert in intellectual disability and mental health.
Clearly, effective early intervention for these children is needed. It could target factors shown to influence their mental health, including improving parent-child relationships, reducing family poverty and other deprivation, and increasing parental mental well-being.
A mainstream issue
A significant proportion (35% to 40%) of children with intellectual disability may have mental health problems. Put another way, 14% of all children with a mental health problem will also have an intellectual disability. This figure represents large numbers of children with significant needs: approximately 85,000 in England and 50,000 in Australia.
So this has to be accepted as a mainstream issue rather than a specialist area. These children represent a high-risk group whose needs have to be addressed by mental health services generally. There are a number of key issues.
Even where there are specialist child intellectual disability mental health services available, such as in many areas of the United Kingdom, practitioners have only a very small evidence base from which to draw.
There are few assessment tools to help clinicians identify mental health problems in these children, especially in those with more severe disability. The evidence base for treatment options is also very small.
Children with intellectual disability are often excluded from mainstream trials of mental health treatments, and specialised research focused only on them has been rare.
We need to invest in developing methods for identifying mental health problems in children with intellectual disability, and to test treatment approaches. And we need a greater understanding of the barriers to accessing mental health services faced by them and their families.
A combination of better evidence and improved access to treatment should help ensure that the mental health problems of children with intellectual disability are recognised and treated.
Emeritus Professor Bruce Tonge, Associate Professor Kylie Gray and Dr Glenn Melvin are from the School of Clinical Sciences at Monash Health, Faculty of Medicine, Nursing and Health Sciences at Monash University. Professor Richard Hastings and Dr Vaso Totsika are from the Centre for Educational Development, Appraisal and Research, University of Warwick, UK.
This article first appeared in The Conversation.