On 11 and 18 June 2026, ACAMH will host a short course Assessment and Management of Intellectual Disability and Co-occurring Conditions.
We caught up with one of the speakers – Dr. Ashley Liew, Consultant Paediatric Neuropsychiatrist at Evelina London Children’s Hospital and South London and Maudsley NHS Foundation Trust, and Vice-Chair of the Child and Adolescent Intellectual Disability Psychiatry Network (CAIDPN) – about the topic, the state of the field, and what attendees can expect.
What drew you to this specialism – and what’s kept you here?
Following my training, I found myself drawn to children with neurodevelopmental conditions. Children with an intellectual disability (ID) very often have co-occurring neurodevelopmental and neurological conditions, and understanding how those interact is genuinely fascinating, clinically.
What’s kept me here is the community – both professionals and families. Many people working in this area have some personal connection to ID, and that shared experience gives the work a particular energy. The field is getting more recognition in recent years: the evidence base is growing, services have improved, and research funders are much more engaged.
If co-occurring conditions are so common in children with ID, why is it so hard to get the right diagnoses?
The first problem is recognition – not just recognising that co-occurrence is common, but the variety of ways in which it presents. When a child has ID alongside one or more co-occurring conditions, the permutations produce a heterogeneity of presentations that changes almost everything about how you assess and support them.
Then there is the question of assessment tools. Standard instruments were developed and validated on neurotypical populations. They were not designed with this group in mind. Apply them without adaptation and you risk producing results that look meaningful but aren’t, or missing things entirely, and that really impacts not just diagnosis, but formulation and support.
Diagnostic overshadowing is also a real issue. If ID becomes an explanatory catch-all – ‘of course they’re struggling, they have ID’ – a co-occurring condition may go unidentified. ADHD, anxiety and a physical condition like constipation causing pain can all be overlooked in this way. And once a co-occurring condition is identified, it should take real prominence in formulation and clinical priorities – the presence of ID should be shaping how you understand and respond to everything else in the picture.
How do you assess for ADHD or autism in a child who is non-verbal, or whose cognitive level is closer to a toddler’s than their chronological age suggests?
Take for example a non-verbal twelve-year-old whose cognitive functioning is at the level of a two or three-year-old. A degree of hyperactivity is entirely normal in a toddler – so when assessing for ADHD, you have to think carefully about how much of what you’re observing is pervasive and functionally impairing in a way that would justify a diagnosis. There’s no validated tool that makes that distinction cleanly. For autism, the ADOS (Autism Diagnostic Observation Schedule) presents similar problems: a child who doesn’t engage with a task as expected may score in a way that looks like social communication difficulty, when it actually reflects their ID.
Innovation doesn’t mean a new instrument – it’s about recognition that adaptations are necessary, the clinical discipline to make them thoughtfully, and the willingness to spend more time: serial observations across different settings, a comprehensive developmental history, and input from school staff and others in the child’s life. Clinicians should also bear in mind that parents of children with ID have higher rates of mental health difficulties and may themselves have ID, which adds a further layer to how that history is gathered.
The field uses the phrase ‘behaviours that challenge’ deliberately – why?
It signals that the behaviour is a challenge to the environment and the people around the child – not simply a problem located within the child which needs to be ‘fixed’. We need to understand what function the behaviour serves. That means thinking about antecedents – not just immediate triggers but background factors like pain, discomfort, or disruption to routine – the behaviour itself, and the consequences: how the environment responds in ways that might inadvertently reinforce it.
This framing is central to positive behaviour support, increasingly well-established in the UK, which provides both the ethical framework and the practical structure for this kind of child-centred assessment. It asks us to think about how we modulate the environment or interactions around the child, rather than defaulting to the expectation that the child simply adapts.
Who should attend this course – and what should they be able to do differently when they leave?
The course is designed for clinicians who have some foundational training and are now encountering the overlap between intellectual disability and neurodevelopmental or mental health conditions in their practice.
This patient population is often considered ‘complex’, but actually I want to push back on that word a little. The word can sometimes put people off, leaving clinicians, school staff and others feeling powerless, assuming this is territory for specialists only. This course is designed to support clinicians’ thinking and ability to adapt to working with this group, rather than be intimidated by that apparent complexity.
Attendees should leave with concrete frameworks for assessment, formulation, and thinking about behaviours that challenge – and with a sense that this is not just manageable but genuinely rewarding work.
Find more content from Dr. Ashley Liew and other experts on intellectual disabilities and more on ACAMH Learn, our completely free, online learning resource.