Neurodiversity 101: Movements... and the intersection of Tourette Syndrome, ADHD, and DCD

This month is both ADHD awareness and DCD awareness weeks and month...

It has made me think about the world of neurodiversity and how we often think about things in boxes... when there is often co-occurrence or overlap.

What does that mean when we think about the intersection of Tourette syndrome (TS), Attention-Deficit/Hyperactivity Disorder (ADHD), and Developmental Coordination Disorder (DCD) ( also known as Dyspraxia) and it made me consider the intriguing overlap in movement-related challenges that have some common themes ( and differences) across all three conditions.

It is important that we consider these differences otherwise we can so easily attribute some challenges more to one condition or another rightly or wrongly especially if we have training in siloes or work professionally in that way.

While each of these conditions has distinct characteristics, we know they often co-occur and may share underlying neurobiological similarities.

I wanted to explore and share these connections with you and consider what they mean for diagnosis and treatment/support/intervention and service design models.

Co-occurrence

One of the most fascinating aspects of these conditions is how frequently they co-exist or overlap with each other.

We see this across many neurodevelopmental conditions but often services are presented in a one diagnosis pathway resulting in parents with their children and adults needing to knock on a lot of doors.

• TS and ADHD : Approximately 60-80% of individuals with TS also have ADHD.
• TS and DCD: While precise figures are unavailable, motor coordination difficulties are frequently observed in individuals with TS.
• ADHD and DCD : About 50% of children with DCD also have ADHD.

These high rates of co-occurrence suggest to me that there may be a shared neurobiological mechanisms or risk factors linking these conditions.( I am not alone thinking this!)

• Tic disorders are frequently overlaps with ADHD, OCD, anxiety, and depression
• DCD is commonly associated with ADHD, autism spectrum disorder, and developmental language disorder

What are the shared features... movements...

All three conditions are classified as neurodevelopmental disorders, meaning they arise during brain development and typically manifest in childhood. This common origin underlines the potential for overlapping pathways in the brain.

Motor control challenges

Though they manifest differently, each condition involves motor control difficulties and it is this that I am particularly interested in:

• TS: Characterised by motor tics—sudden, repetitive movements.
• ADHD: Hyperactivity often includes excessive fidgeting and restlessness.
• DCD: Marked by difficulties with motor coordination and skill acquisition.

Executive function deficits

Another shared feature is challenges in executive function, affecting impulse control, planning, and organisation in all three conditions. This overlap can lead to challenges in daily activities, from managing schoolwork to engaging in social interactions.

What are the differences?

While these conditions share some similarities, there are crucial distinctions that affect how they are experienced and treated:. This may be when challenges are identified. e.g.

• ADHD symptoms usually appear between ages 3-6 years
• Children with more 'severe' impacting ADHD are typically diagnosed around age 5 years
• Parents typically first noticed tics in children at about 6 years of age on average (in early elementary school). The average time from initially noticing tics to receiving a diagnosis of TS was about 2 years .
• The average age of diagnosis e.g. in Netherlands is around 7 years

What are the primary or core symptoms?

• TS: Motor and vocal tics are the hallmark of TS.
• ADHD: Characterised by inattention, hyperactivity, and impulsivity. ( this may include constantly fidgeting and excessive physical movement)
• DCD: Defined by significant impairment in motor coordination.

What are the nature of movement issues?

• TS: Movements are involuntary, repetitive, and suppressible for short periods.
• ADHD: Hyperactive movements stem from internal restlessness and are more generalised.
• DCD: Motor difficulties arise from instability, lower tone, poor planning and execution, rather than an excess of movements.

What are the underlying mechanisms?

Although we don’t fully understand the underlying mechanisms of these conditions, there is some research that may point to some common threads:

• Basal Ganglia Involvement: All three involve dysfunction in the basal ganglia, a brain region crucial for motor control.
• Dopamine dysregulation: Abnormal dopamine signalling plays a role in both TS and ADHD and may also be involved in DCD too.
• Neurodevelopmental trajectories: These conditions may represent different manifestations of atypical neurodevelopment, with shared risk factors but diverse outcomes.

So what does this all mean?

Although TS, ADHD, and DCD are distinct disorders, their frequent co-occurrence and shared features in motor control and executive function suggest interrelated neurobiological pathways. They all commonly overlap - and so we shouldn't miss out considering for example DCD everytime we screen for ADHD for example...

Understanding these intersections can help inform more holistic and effective treatment approaches, ensuring that individuals receive the support they need in managing these overlapping challenges.

There is a need for training of health and educational professionals to be aware of the intersection and overlap between conditions otherwise we are too often going down a single siloed approach to diagnosis will not support the needs of the individual and can end up even being more confusing!

George Eliot's said "It is a narrow mind which cannot look at a subject from various points of view".

Blog Author

I am Amanda Kirby, CEO of Do-IT Solutions a tech-for-good company that delivers consultancy and guidance, consultancy, training and web-based screening tools that have helped 10s of 1000s of people.

Contact us and we can discuss how we can help.

We strive to deliver person-centered solutions relating to neurodiversity and wellbeing.I am a mixed bag of experiences and skills and have 25+ years of working in the field of neurodiversity.

I am a medical doctor, Professor, and have a Ph.D. in the field of neurodiversity; most important of all I am a parent and grandparent to neurodivergent wonderful kids and am neurodivergent myself.

I have written 10 books so far.Theo Smith and I wrote the UK award-winning book?Neurodiversity at Work Drive Innovation, Performance, and Productivity with a Neurodiverse Workforce . My 11th book came out in 2023 Neurodiversity and Education . Theo and I are writing a new book this year about parenting and neurodiversity!

*These are all my own views.