This still applies to just about every mental disorder (it's never everyone, including with adhd, but usually a lot of people).

Ever had a minor hallucination? Hallucinations are a symptom of schizophrenia. Ever had an irrational fear of a social interaction? Symptom of social anxiety disorder.

It's always about magnitude and frequency, i.e. having a major negative impact on your daily life.

Can even happen with physical things - I get a lot of visual snow, but I do not have visual snow syndrome because I have none of the other symptoms so it's not a problem whatsoever.