Why ADHD and autism are so often confused
Both ADHD and autism are neurodevelopmental conditions — they affect how the brain develops and processes information. Both are present from birth, both affect attention and social functioning, and both are frequently missed in women and girls.
Because they share so many surface-level traits, they're regularly mistaken for each other — both by individuals trying to understand themselves and by clinicians who don't specialise in neurodevelopmental conditions. A study by Young et al. found that autistic women are significantly more likely to receive an ADHD diagnosis before their autism is identified, and vice versa.
The key difference — why it matters
The most useful way to understand the core difference:
- ADHD is primarily a difference in attention regulation and impulse control, rooted in dopamine and norepinephrine dysregulation. The fundamental struggle is getting the brain to focus on the right things at the right time.
- Autism is primarily a difference in social information processing and sensory experience, rooted in different patterns of neural connectivity. The fundamental difference is in how the brain processes the social and sensory world.
ADHD core traits
- Difficulty sustaining attention
- Impulsivity
- Hyperactivity (physical or mental)
- Executive dysfunction
- Emotional dysregulation
- Time blindness
Autism core traits
- Social communication differences
- Sensory processing differences
- Need for routine and sameness
- Deep, focused interests
- Literal thinking
- Monotropic attention style
Traits that look the same but feel different
Several traits appear in both ADHD and autism but have different underlying causes:
Difficulty paying attention
ADHD: Attention is dysregulated — hard to direct, easy to lose. The brain gravitates towards stimulation and novelty. Tasks that are boring or unimportant are almost impossible to start or sustain.
Autism: Attention is monotropic — intensely focused on one thing at a time. Autistic people can pay deep, sustained attention to areas of interest but struggle to shift attention when required. Difficulty attending to social cues is a feature of how autistic brains process social information.
Social difficulties
ADHD: Social difficulties arise from impulsivity (interrupting, talking over people, saying things without thinking), distractibility (losing track of conversations), and emotional dysregulation (overreacting, difficulty managing conflict).
Autism: Social difficulties arise from differences in processing social information — difficulty reading facial expressions, interpreting tone of voice, understanding implied meaning, and knowing unwritten social rules.
Emotional intensity
ADHD: Emotional dysregulation is a core feature — emotions are felt intensely and managed poorly. Rejection sensitivity (extreme emotional pain in response to criticism or perceived rejection) is particularly common.
Autism: Emotional experiences can be intense and difficult to identify or communicate (alexithymia — difficulty identifying one's own emotions — is common). Emotional regulation can be affected by sensory overload or unexpected changes.
Repetitive behaviours
ADHD: Repetitive or fidgety behaviours (leg-bouncing, nail-biting, doodling) are related to stimulation-seeking and hyperactivity.
Autism: Repetitive behaviours (stimming — hand-flapping, rocking, humming) serve as sensory regulation tools and are a core part of autistic experience.
Not sure which fits you better?
Our adaptive quiz screens for both ADHD and autism traits simultaneously, and can identify when both are indicated — suggesting an AuDHD profile.
Take the free assessment →Can you have both? — AuDHD
Yes — and it's more common than most people realise. Between 50% and 70% of autistic people also meet criteria for ADHD. The co-occurrence is so consistent that researchers have proposed shared genetic underpinnings. Until 2013, the DSM prevented a dual diagnosis — but current guidance (DSM-5 and ICD-11) explicitly allows both.
When both are present, the combination — informally called AuDHD — creates a distinct experience that's different from having either alone, because the two conditions often pull in opposite directions.
Which should I get assessed for?
If you're unsure whether your traits align more with ADHD or autism, the most important thing is to get assessed for both. Mention both conditions when approaching your GP. Many services only assess for one unless explicitly asked to assess for both.
Our free quiz screens for both simultaneously and can help you understand which traits are most prominent before you seek a formal assessment.