Autism vs ADHD: understanding differences, overlaps and diagnosis

Autism and ADHD are two distinct neurodevelopmental conditions that can impact a person’s ability to navigate daily life. While each condition has its own set of characteristics, they also share some similarities and overlap, which can sometimes complicate diagnosis and management.

Understanding the differences and similarities between autism and ADHD is important to ensure that people get the right support.

Autism vs ADHD

Autism has a number of characteristics that can vary widely between people. Key signs of autism include:

• Social communication challenges – autistic people might find it hard to pick up on social cues or struggle to keep up with conversations. This can make it challenging to connect with others and maintain friendships
• Special interests – they might have an intense enthusiasm for particular subjects or activities, that capture most of their attention and time
• Repetitive behaviours – autistic people might engage in repetitive behaviours and movements, such as repeating certain phrases and sounds, and having very specific routines. These behaviours can provide comfort or help manage anxiety
• Sensory sensitivity – autistic people might have unusual reactions to the way things sound, feel, taste, smell or look. They might find these sensory inputs to be overwhelming, or might not react to things that usually cause a sensory response in other people

In contrast, ADHD symptoms primarily involve issues with attention regulation, impulsivity and hyperactivity, that can impact daily life and learning. These may include:

• Inattention – people with ADHD may struggle to focus on tasks, miss details and don’t seem to listen when they’re being spoken to directly
• Hyperactivity – they might seem to be moving constantly, fidgeting, not being able to stay in their seat, and have a general sense of restlessness
• Impulsivity – people with ADHD might act without appearing to think about the consequences and how their behaviour might impact on other people. For example, interrupting conversations and not being able to wait their turn are some common impulsive behaviours
• Time management and organisation – they might struggle to organise tasks, frequently lose personal items and find it challenging to meet deadlines

Recognising overlapping symptoms

While there are clear differences between autism and ADHD, they also share a number of traits, which can sometimes make diagnosis challenging. Common overlapping symptoms include:

• Difficulties in maintaining focus – people with autism and ADHD can struggle with concentration, although the reasons for this can vary. For example, autistic people may become distracted due to overwhelming sensory sensitivities, whereas people with ADHD might be more inattentive generally
• Interruptive behaviour – both might have interruptive behaviours, such as speaking out of turn. However, in autism, this might stem from challenges in being able to understand social cues, whereas in ADHD, it’s often due to impulsivity
• Emotional dysregulation – people with autism and ADHD can both sometimes find it hard to regulate their emotions, leading to mood swings. Autistic people might have a strong emotional reaction to changes in their routine, while someone with ADHD might respond in a similar way when they’re frustrated or disappointed
• Hyperactivity – some autistic people might display hyperactive behaviours, such as excessive and repetitive movements, especially when they’re stressed or overwhelmed. Similarly, people with ADHD may struggle to sit still and always seem to be moving

These shared characteristics can lead to misdiagnosis or not spotting when both autism and ADHD are present in the same person. It’s important for healthcare professionals to consider the full range of behaviours associated with autism and ADHD when they’re assessing a child or adult. This thorough understanding means they can ensure that any support plans are tailored to each person’s unique needs.

When to seek a diagnosis and what to expect

Recognising when the signs of autism or ADHD are significant enough to need a professional evaluation is a crucial step towards getting the right support. If you notice persistent issues in social communication, focus or behaviour that differ from people of a similar age and developmental level, then it might be time to reach out for an evaluation and potential diagnosis.

Documenting these behaviours and symptoms can provide valuable insights for healthcare professionals. It’s a good idea to keep a record of specific instances of concern, noting patterns that emerge and situations where these behaviours are most obvious.

If you’re concerned about yourself or your child, you may wish to reach out to your GP for an initial discussion. They’ll be able to explore your symptoms, conduct any relevant autism or ADHD screening tests, and refer you to a specialist psychologist or psychiatrist for a formal assessment, if they think this is needed.