I suspect this is the case with many mental health conditions / neurodiverse conditions; after all, people grow up with them and if their environment is not affected or making observations (e.g. people are told or convinced that what their brains do or tell them is abnormal), why would they doubt themselves?

But this is a narrow path to walk, because if you see something and someone tries to convince you it's not there, who is right?

This is why some mental health conditions are pretty terrifying, because doubting your own mind is terrifying.