Overlapping Traits
ADHD and autism are separate neurotypes, but several traits show up in both: difficulty with executive functioning, sensory sensitivities, trouble with transitions, and differences in emotional regulation can all appear whether someone is autistic, has ADHD, or both. This overlap is one reason adults often find it genuinely hard to work out, on their own, which set of experiences best explains their life.
Some traits that look identical on the surface can have different underlying reasons. Difficulty with transitions, for example, might reflect a need for routine and predictability in autism, or a difficulty shifting attention between tasks in ADHD. Telling these apart is exactly the kind of judgement a trained psychologist is equipped to make, drawing on developmental history as well as the presenting experience itself.
Why Co-occurrence Is Common
Research consistently shows that ADHD and autism co-occur more often than chance would predict, with a substantial proportion of autistic adults also meeting criteria for ADHD, and vice versa. Having traits of both is not unusual or a sign that something has been misunderstood; it is a recognised and increasingly well-studied pattern in adult neurodevelopmental research.
For adults with both, life experiences can be shaped by an interplay between the two: sensory sensitivity from autism combined with restlessness from ADHD, for example, or a need for routine alongside a tendency to lose track of time. Untangling this combination is part of why a coordinated assessment approach is valuable, rather than assessing one neurotype while overlooking the other entirely.
Why It Is Hard to Tell From the Outside
Because the two neurotypes can look similar in everyday life · restlessness, social fatigue, sensory overwhelm, or trouble with routines · adults frequently spend years wondering which label, if either, fits. Online quizzes and social media content tend to flatten this complexity into simple lists, when in reality distinguishing between ADHD traits, autistic traits, and traits that reflect both requires a trained clinical eye and structured assessment tools.
It is also common for one neurotype to mask the other. Strong social scripting learned to manage ADHD-related impulsivity, for instance, can make underlying autistic social communication differences harder to spot without a detailed developmental history, and the reverse is also true.
Why Guessing Is Not Enough
Guessing which neurotype applies, or assuming it must be one or the other, can lead to seeking the wrong kind of support, or missing support that would genuinely help. A proper assessment does not start from an assumption; it gathers your developmental history and current experiences, applies standardised tools for both ADHD and autism, and lets a psychologist interpret the full picture rather than forcing your experiences into a single category prematurely.
This matters practically too: strategies that help with ADHD-related executive functioning are not always the same as strategies that support autistic sensory or social needs, so an accurate understanding of which is at play, or whether both are, shapes what kind of support will actually be useful afterwards.
How a Combined Assessment Differs From Two Separate Ones
Completing two entirely separate assessments, one for ADHD and one for autism, often means repeating large parts of your developmental history twice, at extra cost and with two disconnected reports that do not speak to each other. A combined assessment instead gathers your history once and considers both neurotypes together throughout the same coordinated process.
This also allows your psychologist to consider how traits interact, rather than assessing each neurotype in isolation, which produces a more coherent and genuinely useful written report at the end, particularly for adults whose experiences do not sit neatly within a single category.
What If the Assessment Finds Only One Neurotype?
Choosing a combined assessment does not assume the outcome in advance. It is entirely possible, and common, for a combined assessment to find that only ADHD, or only autism, applies, once the full picture has been considered. Approaching the process with both possibilities open, rather than guessing beforehand, is exactly the point of a properly conducted combined assessment, and either outcome is treated as a valid and useful result.
Our Combined Assessment Pathway
For adults who suspect both may be relevant, or who simply are not sure, we offer a combined ADHD and autism assessment pathway that looks at both neurotypes within a single, coordinated process. This avoids the need to complete two separate assessments from scratch and gives you one integrated report covering both areas.
You can read more about how this combined pathway works, including timing and what is involved, on our ADHD and autism assessment page. This article is educational information only, not a diagnostic tool, and cannot tell you which neurotype applies to you · a full assessment with a psychologist is the only reliable way to find out, and a free triage call is a good place to start that conversation.