AuDHD: when ADHD and autism overlap

Autism and ADHD were once thought to rule each other out. It's now understood that a significant number of people have both. Here's what AuDHD actually means.

AuDHD is the informal term for having both autism spectrum disorder and ADHD. It isn't an official diagnostic label, but it's widely used because the two conditions overlap far more often than was once assumed.

Until 2013, the diagnostic manual used in the UK and US actually stated that autism and ADHD could not be diagnosed in the same person. That rule has since been removed, and research now suggests that somewhere between a third and a half of autistic people also meet the criteria for ADHD.

Why the two conditions were kept separate for so long

Autism and ADHD can look like they pull in opposite directions. Autism is often associated with a strong preference for routine and predictability. ADHD is often associated with restlessness and a need for novelty. On paper, they can look contradictory.

In practice, many AuDHD people describe both patterns existing at once, sometimes shifting depending on the day, the environment, or how much energy they have left. Needing structure and routine to feel safe, while also finding it almost impossible to actually follow that routine, is a common and genuinely exhausting combination.

What AuDHD can look like day to day

• •Craving structure and routine, but struggling to maintain it consistently
• •Intense focus on specific interests, alongside real difficulty starting tasks that don't interest you
• •Sensory sensitivity combined with impulsivity, which can feel like being overwhelmed and understimulated at the same time
• •Social exhaustion from masking both conditions at once
• •Meltdowns or shutdowns that build up from a mix of sensory overload and emotional dysregulation

Because the traits of one condition can partially mask or mimic the other, AuDHD is often missed entirely, or only one half of it gets diagnosed. Someone might be assessed for ADHD and told their attention difficulties fully explain their experience, when autism is also part of the picture, or the other way round.

"I spent years being told I was too organised to have ADHD and too chatty to be autistic. Turns out I was masking both at the same time."

— An AuDHD adult describing their diagnosis journey

Why a combined diagnosis matters

Getting the full picture matters because treatment and support that works well for ADHD alone doesn't always translate directly to someone who is also autistic, and vice versa. Some ADHD medications, for example, can increase anxiety or sensory sensitivity in autistic people, which means titration sometimes needs to be slower and more carefully monitored.

Support strategies also differ. Advice aimed purely at ADHD, like "just build more flexibility into your routine", can be genuinely unhelpful advice for someone who relies on routine to manage autistic traits. Understanding both halves of the picture leads to support that actually fits.

Getting assessed for both

Not every clinic offers combined ADHD and autism assessments, so it's worth checking this specifically before booking. If you're already going through an ADHD assessment and recognise autistic traits in yourself as well, mention this clearly at the start of the process rather than waiting to bring it up later.

If this sounds familiar

There's no need to have a full answer before seeking an assessment. A good clinician will help untangle which traits belong to which condition, or recognise where they overlap. What matters most is finding a service that takes both possibilities seriously from the outset.