ADHD vs autism
ADHD and autism share several features and often occur together — a combination only formally recognised since 2013. What distinguishes them.
In short
- Both are neurodevelopmental conditions beginning in childhood, and both affect executive function.
- A rough distinction: ADHD often involves seeking stimulation and novelty; autism often involves seeking predictability.
- Diagnostic systems only allowed both diagnoses together from 2013 — before that, autism took precedence.
- They co-occur frequently, and the combination is sometimes informally called AuDHD.
- The distinctions below are patterns, not tests. Overlap makes this genuinely difficult to assess.
ADHD and autism are separate conditions with real differences, but they share enough that distinguishing them can be difficult — and a substantial number of people have both.
This matters historically. Until the DSM-5 was published in 2013, the diagnostic manual did not permit ADHD to be diagnosed alongside autism. Anyone assessed before then who met criteria for both would typically have received only the autism diagnosis, which is one reason a lot of adults are picking up an ADHD diagnosis late.
What they have in common
- Neurodevelopmental origin. Both begin in childhood and both are highly heritable.
- Executive function difficulties. Planning, starting tasks, switching between them, and working memory.
- Social difficulties — for different underlying reasons.
- Sensory sensitivity. Long recognised in autism, increasingly reported in ADHD too.
- Emotional regulation difficulties and being overwhelmed by intense input.
- Intense focus on interests — hyperfocus in ADHD, special interests in autism.
- Masking. Suppressing traits to appear typical, at considerable cost.
- Both frequently missed in girls and women.
Where they typically differ
| ADHD | Autism | |
|---|---|---|
| Relationship to routine | Often resists routine; finds sameness boring and craves variety. | Often relies on routine; unexpected change can be genuinely distressing. |
| Novelty | Actively seeks it. Interest fades once something is familiar. | Often finds it stressful. Depth and familiarity are preferred. |
| Focus of interests | Intense but frequently shifting — a new absorbing subject every few months. | Often deep, detailed and sustained over years. |
| Social difficulty, and why | Interrupting, talking over, missing what was said, impulsive comments — a regulation problem. | Difficulty reading implicit social rules, unspoken expectations and indirect communication. |
| Communication style | Fast, tangential, jumping between topics. | Often precise and literal; may find implication and subtext harder. |
| Repetitive behaviour | Fidgeting, restlessness, movement for stimulation. | Self-soothing repetitive movement, and strong preference for repeated sequences. |
| Change of plan | Often welcome — it relieves boredom. | Often difficult, particularly without warning. |
When someone has both
Having both is common enough that people have coined the informal term AuDHD for it. It is not a clinical diagnosis — the formal position is two separate diagnoses — but it names something real, because the combination is not simply one plus the other.
People with both often describe genuinely conflicting pulls:
- Needing routine to function, and being unable to sustain one.
- Craving novelty and finding it exhausting.
- Wanting social contact and being drained by it.
- Planning meticulously, then being unable to follow the plan.
This can make each condition harder to spot. ADHD traits can obscure autistic ones and vice versa, which is part of why the combination is often identified late.
Why this is hard to assess
Distinguishing these conditions — or identifying both — takes a detailed developmental history and clinical experience with each. It is not something to resolve from a comparison table, including this one. If both seem to fit, say so at the appointment; it is useful information rather than a complication to hide.
Does it matter which it is?
Yes, mainly because the support differs. ADHD has established medication options. There is no medication for autism itself, though medication may be used for co-occurring conditions. Practical strategies also diverge — someone whose difficulty is boredom with routine needs something different from someone distressed by disruption to it.
Where both are present, treating only the ADHD can leave significant needs unmet, and support planned only around autism can miss why tasks never get started.
Common questions
Can you be diagnosed with both ADHD and autism?
Yes. Since 2013 the diagnostic criteria have explicitly permitted both, and the combination is now recognised as common. Anyone assessed before that date may have received only one, and can be reassessed.
Is ADHD on the autism spectrum?
No. They are separate diagnoses. Both fall under the broad umbrella of neurodevelopmental conditions, and "neurodivergent" is often used informally to cover both, but ADHD is not part of the autism spectrum.
Do ADHD medications help autism?
They treat ADHD symptoms, including in people who also have autism, though response rates and side effects can differ. They do not treat autism itself. This is a decision for a prescriber who knows both diagnoses.
Which should be assessed first if I think I have both?
Availability and waiting times often decide this in practice. Raise both with your doctor at the outset rather than one at a time, so the assessment considers the full picture from the start.