Earlier quoted context omitted.
There’s a view that ADHD is badly named, because many ADHD people have incredible focus (at times), and many are not hyperactive in the least. It’s more of an issue about emotional dysregulation, which can be exceptionally painful for those who suffer.
> because many ADHD people have incredible focus (at times) The concept of "hyperfocus" as a symptom of ADHD is relatively recent idea. It didn't appear in any medical literature for a long time. The first appearance I could find was in some author's book about ADHD, which wasn't even targeted at medical professionals. It might be a symptom for some people, but misinterpreting it as a symptom of ADHD leaves the door…
Hyperfocus is a symptom of ADHD, ASD, and schizophrenia [1]. So a person who experiences hyperfocus may be experiencing one or more of those conditions. (Although, when I say "symptom", not necessarily a diagnostic one – conditions can have both diagnostic symptoms, which form part of the diagnostic criteria, and non-diagnostic symptoms, which don't, but nonetheless have been commonly observed clinically and/or in research in those formally diagnosed.)
Since it is possible to have subclinical manifestations of psychiatric diagnoses, a person who experiences hyperfocus without meeting the diagnostic criteria for any of these diagnoses may have such a subclinical manifestation of one or more of them. The formal name for subclinical ASD is "Broad Autism Phenotype" (BAP) [2]; I don't think subclinical ADHD [3] or subclinical schizophrenia [4] have distinctive names, but both have been researched. (A lot of people who incorrectly self-diagnose themselves as having X despite not actually meeting the diagnostic criteria, may in fact be correctly identifying the existence of subclinical traits of X in themselves.)
[1] https://pubmed.ncbi.nlm.nih.gov/31541305/
[2] e.g. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5949081/
[3] https://www.sciencedirect.com/science/article/abs/pii/S01918...