Many adults first wonder about autism after a child is diagnosed, after burnout, or after years of feeling different without a name for it. No single sign confirms it, and no checklist can. What clinicians assess is a lifelong pattern in two areas, and how that pattern affects daily life.
NICE's guideline for adults (CG142) points assessors to two groups of features: persistent difficulties in social interaction and communication, and repetitive behaviours, resistance to change or restricted interests. It also tells assessors to look at sensory sensitivities and attention to detail.
In daily life, the first group can look like finding social cues hard to read or return, preferring literal language, finding small talk or knowing when a conversation has ended difficult, or finding friendships tiring to keep up. The second can look like needing a predictable routine and being thrown by sudden change, a very deep interest in a few subjects, repeated movements or phrases that help you settle (often called stimming), and strong reactions to sound, light, texture or smell. These are examples of how the features can appear, not a test, and they vary a great deal between people.
Nobody needs to show every trait. Clinicians ask whether the pattern has been there since childhood, whether it appears across different settings, and whether it causes real difficulty with work, study or relationships. Some adults have learned to hide or work around their difficulties, so the picture can look quite different from how it looked in childhood. See autism in women and masking.
For adults without a learning disability, NICE uses a short screening questionnaire, the AQ-10. Under CG142, a score of 6 or above, or clinical suspicion, is a reason to offer a full assessment. It is a screen, not a diagnosis. AsIAm, Ireland's autism charity, notes that many people complete online self-assessments first but that they are not diagnostic. A high score tells you that talking to a clinician is worthwhile, and nothing more.
Anxiety, depression, social anxiety, OCD and ADHD can look similar to autism or sit alongside it, and CG142 tells assessors to consider them. That is the main reason not to rely on a checklist, and why a diagnosis should come from a trained clinician. See autism and ADHD together.
The next step is a conversation with a clinician. In England that usually starts with your GP. In Ireland, AsIAm states there is no public pathway for adult autism assessment, so most adults see a private psychologist or psychiatrist. Our guide to getting an autism assessment as an adult in England and Ireland covers the routes, and what happens at an adult autism assessment covers the appointment itself.
The features and the AQ-10 threshold are taken from NICE CG142 (recommendations 1.2.2, 1.2.3 and 1.2.7). The Irish position is taken from AsIAm's guidance on adult diagnosis. We did not use clinic websites as sources. Last checked 25 October 2026. This article describes how assessment services work. It is general information, not medical advice, and it cannot assess your individual situation. Reviewed by: Proco Team.