Understanding mental illness in children with intellectual disabilities

Professor David Skuse is a child psychiatrist and researcher based at University College London. He believes that children with intellectual disabilities haven’t received the support they need from mental health services.

Improving mental health support for these children needs sustained investment in research. However, child psychiatry and intellectual disabilities have been chronically under-funded fields of research, compared to other areas such as cancer, heart disease, or dementia.

The IMAGINE-ID project

To redress this lack of funding, we partnered with the Medical Research Council (MRC) to provide a total of £2.6 million to better understand the link between intellectual disability and mental health. This money funded the IMAGINE-ID project led by Professor David Skuse, in collaboration with researchers at Universities of Cambridge and Cardiff.

Although intellectual disabilities can be caused by a range of factors, it’s known that 85 per cent of cases have a genetic origin. This means that variations or faults in a child’s genes (mutations that are either inherited or newly occurring) have contributed to their disability. David and his colleagues wanted to investigate whether some rare mutations might be associated with a greater risk of specific emotional and behavioural problems later in life. If we had this information, it would make it possible to provide families, whose children have these very rare genetic conditions, with the information they need about their child’s future and care. At the moment, very little information is available about most of these rare events, which are increasingly being diagnosed by the NHS’s genetic screening programme.

The IMAGINE-ID project has brought together more than 3,500 children with an intellectual disability and a known genetic mutation, making it the largest study of its kind in the world.

The team found that children with intellectual disabilities with a known genetic cause were over 30-times more likely to develop an emotional or behavioural problem, compared to typically-developing children. Nearly half of the children in the study have at least one mental health disorder, and 80 per cent have multiple disorders. More than one in three has an autism spectrum disorder, about one in eight have attention deficit hyperactivity disorder (ADHD), and one in 10 has severe anxiety.

David and his colleagues expected to find that specific genetic mutations would be associated with a greater risk of emotional or behavioural disorders. What they found overall was that the problems the children were experiencing were very similar across the board, regardless of their genetic condition. The research team are now following these children for another five years, to see if the risks to their mental health change as the children become teenagers and young adults.

Providing better information and support

The most immediate impact of the IMAGINEID study is the information that can now be provided to the families of children with rare genetic disorders that are associated with learning difficulties. With data from the study, doctors looking after these children will have greater awareness that many rare genetic conditions are usually associated with a much increased risk of behavioural and emotional disorders. They can also advise parents on the type of problems they might face and make recommendations for managing those problems that might be helpful to them.

David’s also acutely aware of the policy implications of the IMAGINE-ID programme. He will be using the IMAGINE-ID data to study how genetic testing and mental health support for these children varies across the country, such as whether there are differences between affluent areas and poorer areas. In the longer term, David hopes that the IMAGINE-ID project will help to make access to both genetic testing and mental health services much more equitable for children with intellectual disabilities.

Nicole, 10, has a genetic disorder called ‘16p11.2 deletion’, which can cause language impairment and a delay in reaching certain developmental milestones, such as walking or talking, learning new skills or interacting with others.

“Nicole was born a few weeks early and showed some signs of the condition straight away, including having very flexible joints (hypermobility), drooped eyelids and developmental delay” says her mother, Nichola.

“We got involved in the study through Great Ormond Street Hospital several years ago. We were already part of the 1000 Genomes Study and were happy to get involved in more research to help other families in the future."

Brandon has a genetic disorder called ‘22q11 deletion’, which can cause heart defects and learning difficulties.

“Brandon was very lucky, as he only showed some of the problems associated with his disorder, including social difficulties, delayed speech when he was little, and curvature of the spine (scoliosis)”, says his mother, Claudia.

“The information provided by the IMAGINE-ID researchers has been very useful. It highlighted the main difficulties he has, particularly with social interactions.

“The IQ test was also really valuable, particularly for discussions around Brandon’s schooling, as it just proved what we already knew: Brandon is a very intelligent boy, the way he learns and interacts is just different. For example, we realised he was a visual learner, so we allowed him to watch more videos related to his learning, rather than just reading books. Without the IQ test, we might not have pushed him academically as much as we did. Brandon is now doing BTEC science at college, and he got a merit in his first year.”