ADHD is definitely a major cause, but another big one which is much more complex to talk about is “avoidant” type behaviors that are a result of trauma/neglect/abuse early in life.

There is correlation that occurs among diagnoses of ADHD, Autism, CPTSD, and other “mental issues”, such that by the time one becomes noticeable as having pathological effect, then it’s likely to be able to identify at least a few more issues acting in a comorbid manner.