"Is it autism, ADHD, or both?" is one of the questions parents ask us most often. It is a very reasonable question. The two often look alike from the outside, and many children are both autistic and have ADHD.
Understanding which applies to your child matters. It shapes the support they get at home and at school, and whether medication might help. Above all, it helps your child make sense of how their own mind works.
In this article we explain what autism and ADHD are, where they overlap, how clinicians tell them apart, and what happens when a child is both.
What is autism?
Autism is a lifelong difference in how a person experiences the world, communicates and connects with others. It is not an illness, and it is not caused by parenting. Autistic children often have real strengths, such as deep focus on interests, attention to detail, honesty and strong memory.
Autistic children may:
communicate and socialise in their own way, for example finding unwritten social rules confusing or tiring
prefer routine and predictability, and find unexpected change distressing
have intense, focused interests
experience sensory input differently, such as noise, light, textures or food
use repetitive movements or routines ("stimming") to regulate themselves
Many autistic children, especially girls, learn to mask their differences at school. They then become exhausted or overwhelmed at home. You can read more in our article Autism in Girls: Understanding Masking and Why So Many Are Missed.
What is ADHD?
ADHD (attention deficit hyperactivity disorder) is a difference in how the brain manages attention, activity and impulses. It is not about laziness, poor behaviour or a lack of intelligence. Children with ADHD are often creative, energetic, curious and quick to spot new ideas.
Children with ADHD may:
find it hard to start, focus on or finish tasks that do not interest them, yet hyperfocus on things that do
be restless, fidgety or always "on the go"
act or speak before thinking, or interrupt
lose things, forget instructions and struggle with organisation and time
feel emotions quickly and intensely
ADHD can look different in girls. Many are quiet and dreamy rather than hyperactive, so their difficulties are missed. Our article Is It ADHD? Understanding How ADHD Presents in Girls explains more.
Where they look alike, and how we tell them apart
The same behaviour can have quite different reasons behind it. A clinician looks less at what a child does and more at why.
Not joining in with friends
Autism: social rules can feel confusing or tiring, and the child may prefer one-to-one time or friends who share their interests.
ADHD: the child wants to join in, but may interrupt, get bored or act impulsively, so friendships can break down.
Meltdowns or big reactions
Autism: often a sign of overwhelm from change, uncertainty or too much sensory input.
ADHD: emotions arrive quickly and strongly, especially when waiting or being asked to stop something enjoyable.
Not listening in class
Autism: processing spoken language can take longer, or the classroom may be too noisy.
ADHD: attention drifts away, especially when the task is not interesting.
Fidgeting and moving
Autism: movement (stimming) can help with self-regulation or managing sensory input.
ADHD: restlessness and a strong need to move.
Struggling with homework
Autism: instructions may be unclear, or it is hard to switch away from a special interest.
ADHD: getting started, staying organised and keeping going are the hardest parts.
Intense focus on one interest
Autism: a deep, lasting interest that brings comfort and joy.
ADHD: hyperfocus on something stimulating, which may change often.
A good assessment brings together information from home, school and the child themselves. It looks at early development, patterns across different settings, and how the child experiences their own difficulties.
When it is both
Being both autistic and having ADHD is common. In one large US survey, about half of autistic teenagers also had an ADHD diagnosis (Accardo et al., 2022). Estimates vary between studies, but the overlap is far higher than chance.
Until 2013, the main diagnostic manual did not allow both diagnoses to be given together. Many adults and older young people were therefore only ever told about one. Today, clinicians are expected to look for both.
When a child has both, the two can pull in opposite directions. For example, a child may crave routine because they are autistic, yet find it hard to stick to one because of ADHD. Or they may want novelty and excitement, yet become overwhelmed by it. Families often describe this as their child being "in conflict with themselves".
Signs that both may be present include:
ADHD-type difficulties that remain even when the environment is calm and predictable
social differences that go beyond impulsivity or inattention
a child who was assessed for one, but the support is "only half working"
strong sensory needs alongside marked distractibility and restlessness
Why the full picture matters
Knowing whether your child is autistic, has ADHD, or both changes what helps.
At home: autistic children often benefit from predictability, visual schedules and sensory adjustments. Children with ADHD often benefit from short tasks, movement breaks, reminders and immediate praise. Children with both usually need a blend.
At school: a clear report helps the school understand your child and put the right adjustments in place. It can also support an application for an Education, Health and Care Plan (EHCP), if needed.
Medication: ADHD medication can help with focus and impulsivity. It does not change autism, and autistic children may be more sensitive to side effects, so dosing is usually started low and reviewed carefully.
For your child: understanding their own neurotype helps children replace "I'm lazy" or "I'm weird" with a kinder, more accurate story about themselves.
When only one diagnosis is made, the other set of needs can be missed. A child might start ADHD medication and still struggle socially, or receive autism support while their attention difficulties go unrecognised.
What an assessment involves
If you wonder whether your child is autistic, has ADHD, or both, it helps to ask for an assessment that considers both. Otherwise, one set of needs can be missed, and your family may face a second assessment later.
A thorough neurodevelopmental assessment usually includes:
A detailed history of your child's development, health, family and school life.
Questionnaires from parents, the child (where appropriate) and school, to see how the child is in different settings.
Autism-specific assessment, often using structured tools such as the ADOS-2 (time spent with the child) and ADI-R (an interview with parents about early development).
ADHD-specific assessment, often including rating scales and sometimes a computer-based attention test.
Feedback and a written report, explaining the findings and practical recommendations for home and school.
Where to start
Talk to your GP, who can refer your child to local NHS services.
Speak to your child's school, especially the SENCo. Schools can put support in place based on need, without waiting for a diagnosis.
Keep notes of what you notice at home, with examples. These are very helpful at any assessment.
Look after yourself too. Parent support groups and charities can be a great source of understanding while you wait.
Whatever the outcome, an assessment is not about labelling your child. It is about understanding them, so that the people around them can offer the right support.
Source: Accardo AL, Pontes NMH, Pontes MCF. Heightened Anxiety and Depression Among Autistic Adolescents with ADHD: Findings From the National Survey of Children's Health 2016–2019. Journal of Autism and Developmental Disorders, 2022.