The short version: ADHD is primarily about regulating attention, activity and impulse. Autism is primarily about social communication, routine and sensory experience. They're different conditions — and they co-occur often enough that the NHS explicitly notes autism "may also look different in someone who has other conditions, such as ADHD" (NHS).
So the question is frequently not which one, but whether it's both.
Key takeaways
- Different core features. ADHD centres on attention and impulse; autism on social communication, routine and sensory processing (NHS; NHS).
- They co-occur. The NHS names ADHD among the conditions that change how autism presents (NHS).
- Masking hides both, and makes everyday social interaction exhausting (NHS).
- Both are frequently missed in women, who are more likely to mask and to show fewer obvious repetitive behaviours (NHS).
The core differences
| ADHD | Autism | |
|---|---|---|
| Attention | Difficulty regulating it — drifting off, or locking on and being unable to switch | Deep, sustained focus on specialist interests |
| Social difficulty | Usually about impulse: interrupting, talking over, missing cues in the moment | Usually about interpretation: facial expressions, gesture, tone, figures of speech |
| Routine | Routine is hard to maintain, and often resisted | Routine is relied on; changes to it cause distress |
| Repetition | Less characteristic | Repetitive movements (stimming) such as rocking or hand-flapping |
| Sensory | Can be present | Core feature — very sensitive, or not sensitive at all, to light, sound, smell, taste or texture |
| Novelty | Strongly drawn to it | Often finds it difficult |
The autism signs above are the NHS's own list for adults (NHS).
Where they genuinely overlap
This is what makes self-diagnosis unreliable.
Social difficulty, different route. Both can leave you struggling in groups — but an ADHD adult may be interrupting and losing the thread, while an autistic adult may be working hard to decode what people mean. The visible outcome can look identical.
Executive function. Planning, organising, starting and finishing are commonly hard in both.
Masking and exhaustion. The NHS notes that masking can make autism signs less obvious while making everyday activities and social interactions "exhausting and stressful" (NHS). The same dynamic drives ADHD burnout.
Emotional intensity. Both groups commonly report strong, fast-moving emotional reactions — see RSD and ADHD.
Anxiety and low mood on top. Both frequently arrive alongside anxiety or depression, which can be diagnosed first and treated for years while the underlying difference goes unrecognised.
Can you have both?
Yes. The combination is commonly called AuDHD, though that's a community term rather than a clinical one — there's no separate diagnosis, you'd be diagnosed with each condition.
It can feel contradictory from the inside: craving routine while being unable to stick to one, needing novelty while finding change distressing, wanting social contact while finding it depleting. Those aren't inconsistencies; they're two sets of traits pulling in different directions.
Why both are missed in women
The NHS is explicit that autistic women may be more likely to mask, to copy how other people behave, and to show fewer signs of repetitive behaviour than autistic men — and are more likely to be diagnosed with anxiety, depression or an eating disorder instead (NHS).
The pattern in ADHD is similar, and for similar reasons. Our guide to ADHD in women covers it, and inattentive ADHD explains the presentation most often overlooked.
How assessment works
They're assessed separately, usually by different specialists, and either can be assessed first.
An ADHD assessment examines whether difficulties with attention, activity and impulse began in childhood, continued into adult life, appear in more than one setting, and cause real day-to-day difficulty (NICE NG87). Our guide to adult ADHD assessment covers the process.
For autism, the NHS has its own assessment route, which you can be referred to via a GP.
If you suspect both, say so at the outset. Being assessed for one in isolation is how the other gets missed.
When to see a GP
See a GP if these difficulties are affecting your work, relationships or daily life, or if you think you may be autistic, have ADHD, or both (NHS; NHS).
If you're having thoughts of harming yourself, call 111 and choose the mental health option, contact your GP urgently, or go to A&E. Samaritans are free on 116 123, any time (NHS).
Want a starting point on the ADHD side? Our free adult ADHD self-screener takes a few minutes and stores nothing. It does not screen for autism.
Honest FAQs
What's the main difference between ADHD and autism?
ADHD is primarily about regulating attention, activity and impulse. Autism is primarily about social communication, routine and sensory processing (NHS; NHS).
Can you be autistic and have ADHD?
Yes. The NHS names ADHD among the conditions that change how autism presents (NHS). There's no combined diagnosis — you'd be diagnosed with each.
Is AuDHD a diagnosis?
No. It's a widely used community term for having both. Useful shorthand, but it won't appear on a clinical letter.
Which should I get assessed for first?
Whichever fits your difficulties most closely, but tell the clinician you're considering both. Assessing one in isolation is the most common way the other is missed.
Can a questionnaire tell me which one I have?
No. Screening tools can indicate whether assessment is worth pursuing; distinguishing the two requires a specialist looking at your developmental history as a whole (NICE NG87).
Why was I diagnosed with anxiety instead?
Because anxiety and low mood often sit on top of both, and are what people present with. That's especially common in women, who the NHS notes are more likely to be diagnosed with anxiety, depression or an eating disorder (NHS).
