Comment by novok

I think many who have 'adult' ADHD probably had a form of it as a child, but had early interventions or other mitigating factors that made them not assessed as a child. Such as being poor, or being an ADHD inattentive type, or a girl (ADHD can show up differently in girls vs boys), or an inattentive 'twice exceptional' who is also highly intelligent, so they were well behaved and did 'good enough' in school that nobody really thought to give them a neuro-psychological assessment. Or their undiagnosed ADHD parents think their ADHD kid is normal, because it's close to their behavior set and thus never really thought of it being an issue.