Emerging research reveals that a significant number of adults experience overlapping signs of autism and ADHD, challenging traditional diagnostic boundaries and emphasising the need for nuanced understanding and support for neurodivergent adults.
Many adults spend years sensing that something does not quite fit, yet never finding a label that explains why. For some, autism alone does not seem to capture the whole picture; for others, ADHD does not quite fit either. The overlap between the two can be confusing, especially when the signs seem to pull in opposite directions, but experts now say that combination is far more common than once thought.
For years, medical guidance treated autism and ADHD as if they could not occur together. That changed in 2013, when clinicians moved away from refusing an ADHD diagnosis simply because someone was autistic. Since then, research has suggested the overlap is substantial: the Cleveland Clinic says between 50% and 70% of autistic people also have ADHD, while similarly high estimates appear in other health guidance and adult support resources. The result is that many people, particularly those diagnosed later in life, have spent years being misunderstood or overlooked.
Saara Kuvaja, a certified ADHD and AuDHD coach, told Psychologies that late-diagnosed adults often describe a long history of not knowing why ordinary life felt so hard. She said women and girls have been especially likely to be dismissed as anxious or stressed rather than recognised as neurodivergent, in part because most research has focused on boys and men. That gap has helped fuel a sense that people must fit neatly into one diagnosis or the other, when in reality the picture can be much messier.
AuDHD is not an official clinical diagnosis, but a term used to describe someone who is both autistic and has ADHD. Kuvaja said the signs can vary widely, but some patterns are common. A person may love planning but struggle to carry plans through, may crave social contact yet need long periods alone afterwards, or may rely on routine while also becoming bored or overwhelmed by it. These shifts are often tied to executive functioning, the mental processes involved in memory, planning, focus, motivation and impulse control.
Another reason the condition is often missed is masking. Many adults, especially those diagnosed late, learn to hide or compensate for their difficulties so effectively that only the surface is visible to others. Kuvaja compared this to an iceberg: the visible part may look manageable, while the effort underneath is exhausting. That can leave even an ordinary workday feeling draining, particularly when a person is constantly adapting to different demands, moods and environments.
For people who recognise themselves in these descriptions, the next step is usually a separate assessment for autism and ADHD, though some clinicians will evaluate both during the same appointment. In the UK, that may begin with a GP referral or, in England, a Right to Choose pathway. Kuvaja said there is no single right moment to seek diagnosis, but ongoing struggles are a clear sign that support could help. While an assessment can be relieving, she also noted that it can bring grief as well as clarity, especially when answers arrive later in life.
In the meantime, specialists suggest building systems that work with fluctuating capacity rather than against it. That may mean allowing for structure with flexibility, paying attention to energy patterns, and being realistic about what can be managed on any given day. The broader message from clinicians and support groups is simple: if the signs feel familiar, it is worth taking them seriously, whether or not a formal label follows.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
