Autism vs ADHD: Key differences and overlapping symptoms in children

Understanding the differences between Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) is essential for parents seeking clarity about their child’s neurodevelopmental health. Both conditions affect a child’s behaviour, communication and ability to focus, but they have distinct characteristics and require different approaches to diagnosis and management.

It’s important to note that a diagnosis may not always be straightforward from the beginning. Symptoms that seem to suggest Autism or ADHD can also stem from a variety of other potential causes - which we’ll discuss later.

In this article, we talk to leading Consultant Paediatrician, Dr Joe Datt to highlight the key differences and overlapping symptoms of Autism and ADHD, helping parents make informed decisions about their child’s care.

What are Autism and ADHD?

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition that primarily affects social interaction, communication, and may have some repetitive behaviours. Children with autism may struggle with understanding social cues, forming relationships, and adapting to changes in their environment. Sensory sensitivities and highly focused interests are also common traits.

Attention Deficit Hyperactivity Disorder (ADHD) is a condition that impacts attention, impulsivity, and hyperactivity. Children with ADHD may find it difficult to concentrate, sit still, or follow instructions. They often exhibit excessive energy and struggle with impulse control, leading to difficulties in school and social settings.

Key differences between Autism and ADHD

1. Social interaction

• Autism: Children with ASD often find social interactions challenging. They may struggle with eye contact, facial expressions, and understanding emotions. Conversations can be one-sided, and they may prefer solitary play over group activities.

• ADHD: While children with ADHD can be socially active, they may have trouble maintaining friendships due to impulsive behaviour, difficulty taking turns, or talking excessively. Unlike children with autism, they usually seek social interaction but may struggle with appropriate engagement.

2. Communication and language development

• Autism: Speech delays and difficulties with verbal and non-verbal communication are common. Children may have a monotone voice, repeat phrases (echolalia), or struggle with understanding figurative language.

• ADHD: Language development is typically normal, but children with ADHD may interrupt conversations, struggle to stay on topic, or talk excessively due to impulsivity.

3. Attention and focus

• Autism: Children with autism can have intense focus on specific interests, often spending long periods on a particular subject or activity. However, they may struggle to shift attention to other tasks.

• ADHD: Attention span is often short, with difficulty maintaining focus on one activity. Children with ADHD may get easily distracted and move quickly from one task to another without completing them.

4. Repetitive behaviours vs impulsivity

• Autism: Repetitive behaviours (e.g., hand-flapping, lining up toys, strict routines) are hallmark traits. Any disruption to their routine can cause significant distress.

• ADHD: Impulsivity is more prominent, leading to risk-taking behaviours, interrupting others, and difficulty waiting for turns.

Overlapping symptoms of Autism and ADHD

Despite their differences, Autism and ADHD share some overlapping traits, which can sometimes make diagnosis challenging:

• Difficulty with focus: Both conditions can involve inattentiveness, but in different ways (hyper-focus in autism, distractibility in ADHD).

• Hyperactivity: While hyperactivity is a key trait of ADHD, some autistic children may also have high energy levels, though this is less common.

• Difficulty following instructions: Both children with ASD and ADHD may struggle with multi-step instructions, leading to frustration in structured environments like school.

• Sensory sensitivities: Many children with autism experience sensory processing issues, but children with ADHD can also have sensory preferences and aversions.

How to differentiate between Autism and ADHD

Given the overlap, it’s crucial to seek a professional evaluation if you suspect your child may have either condition. Paediatric specialists, such as Dr Joe Datt at Schoen Clinic Chelsea, conduct thorough neurodevelopmental assessments to differentiate between Autism and ADHD, as well as other conditions that may mimic their symptoms, forming part of a comprehensive differential diagnosis.

Dr Joe Datt, Consultant Paediatrician

"Misdiagnosis can happen when we focus too narrowly on Autism or ADHD without considering other possible explanations," says Dr Joe Datt.

"For example, I once assessed a 16-year-old boy who was thought to have ADHD due to his inattention in class. However, after a thorough evaluation, we discovered he had undiagnosed epilepsy and was experiencing absent seizures - brief episodes where he would ‘zone out’ due to neurological activity, rather than symptoms of ADHD. I’ve also seen cases where a child was assumed to have Autism, but the real underlying cause was dyslexia." These are just two of many possibilities, which underscores the importance of seeing a specialist for a thorough evaluation.

Dr Datt continues, "In other instances, rare genetic disorders can present with behaviours that resemble ADHD or ASD, yet once the root condition is identified and managed, those symptoms significantly improve."

Some key questions parents can ask themselves include:

• Does my child struggle with social cues and non-verbal communication? (More likely autism)

• Is my child impulsive, interrupting conversations and acting without thinking? (More likely ADHD)

• Does my child become extremely distressed if their routine changes? (More likely autism)

• Can my child focus intensely on one subject but struggle with shifting attention? (More likely autism)

• Does my child frequently get distracted and jump between activities? (More likely ADHD)

Getting a diagnosis in Chelsea, West London

If you suspect your child may have Autism or ADHD, seeking a diagnosis from a qualified specialist is the first step. Early intervention can significantly improve outcomes, helping children develop skills to manage their symptoms effectively.

At Schoen Clinic Chelsea, Dr Datt and his team offer holistic and comprehensive neurodevelopmental assessments tailored to each child’s unique needs. He stresses the importance of maintaining a broad perspective during diagnosis. "As specialists, we must always ask, ‘What could we be missing? What else could this be?’ rather than rushing to label a child with a specific condition. That’s why neurodevelopmental assessments are so critical. They help rule out other possibilities and ensure we provide the right support tailored to the child’s actual needs.”

The diagnostic process typically includes:

• Parental interviews and developmental history reviews

• Behavioural observations

• Standardised assessment tools

• Collaboration with schools and therapists for a holistic evaluation

Treatment and support options

While Autism and ADHD require different approaches, tailored support can help children thrive.

Autism support strategies:

• Speech and Language Therapy: Helps improve communication skills.

• Occupational Therapy: Addresses sensory sensitivities and motor skills.

• Structured Routines: Maintaining predictability reduces anxiety.

ADHD management strategies:

• Behavioural therapy: Helps with impulse control and social interactions.

• Medication: In some cases, stimulant or non-stimulant medication may be recommended.

• Organisational strategies: Visual schedules and step-by-step instructions improve task completion.

Supporting your child’s journey

Whether your child has Autism, ADHD, or overlapping symptoms, understanding their unique needs is the key to providing the best support. Both conditions present challenges, but with early intervention and appropriate strategies, children can develop essential life skills and thrive in their own way.

If you're in Chelsea, West London, or Greater London and are concerned about your child's development, Schoen Clinic Chelsea offers expert general paediatric consultations, assessments for autism, ADHD, and combined assessments with Dr Joe Datt.

Contact us today to learn more about how we can support your child’s journey to better health and wellbeing.

This page was reviewed by Dr Joe Datt on 14/04/2025.