ADHD and intellectual disability

With under-recognition in referral and diagnosis, Dr Melanie Palmer, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), explains how a project aims to support professionals to better screen ADHD in intellectually disabled individuals.

Please can you tell us about your career to date and what motivates you?

My background is in psychology and I am passionate about using evidence-based practice to improve the health and wellbeing of children and young people.

I have particular interests in understanding and supporting children who have experienced adverse life events, providing early intervention and support for children and parents and carers, and investigating how neurodevelopmental differences can influence development and functioning.

What is ADHD?

Attention Deficit Hyperactivity Disorder (ADHD) is a persistent high-impact, high-cost neurodevelopmental condition usually diagnosed early in life, prevalent in 5.3% of the population.

It is characterised by inattention and hyperactivity/impulsivity problems that are greater than expected for an individual’s age, developmental appropriateness, and intellectual functioning. This leads to functional impairment. ADHD is associated with worse physical and mental health, educational attainment, personal relationships, and overall social functioning.

What’s the relationship between individuals with an intellectual disability and ADHD?

Intellectual disability is defined by significant, generalised impairments in intellectual functioning and everyday life skills. These core characteristics are often accompanied by additional neurodevelopmental conditions, like ADHD. For example, a recent systematic review indicates diagnostic rates of ADHD at 30% in 6 - 21-year-olds with an intellectual disability, in contrast to 5-7% in non-intellectually disabled young people.

However, despite the elevated prevalence of ADHD in intellectually disabled individuals, under-recognition in both referral and diagnosis is common. This means that many young people with both ADHD and an intellectual disability are missing out on effective interventions, such as specific environmental modifications within home and education settings, and psychotropic medication.

Can you introduce us to the ‘Recognising ADHD in Intellectual Disability’ project and what the benefits to patients will be?

The ultimate aim is to identify and validate screening tools for ADHD to use with young people with a co-occurring intellectual disability.

To achieve this, three separate studies (a systematic review, Public and Patient Involvement (PPI) consultations, and quantitative analysis of pre-existing data) form the current research.

Study one, the systematic review, will contribute to literature on the accuracy of existing screening measures used to assess ADHD in young people with intellectual disability.

Study two, the PPI consultations, will extend understanding of the challenges parents and clinicians face with recognising ADHD in children and young people with an intellectual disability and how they would use new or modified measures to help with accurate diagnosis.

Study three will use existing datasets to identify the behaviours and items that best screen for ADHD in young intellectually disabled individuals.

From the work, we hope to help professionals in screening for accurate ADHD referral and diagnosis, and thus increase intervention options and improve outcomes.

How does being part of King’s Health Partners help your work? 

Being part of world-leading King’s Health Partners (KHP) has enabled us to access a wide range of expertise in neurodevelopmental conditions. For example, our expert clinicians who form our advisory group work in some of the specialist neurodevelopmental services across KHP.

Finally - what would your advice be to someone starting out in research?

It’s fun, you are always learning, and it's great to work with such inspiring people here at KHP.

Liked this article? Explore how King's Health Partners Neurosciences brings together world-class research, education and clinical practice across the partnership to drive improved holistic outcomes for patients living with a wide range of neurological conditions.