Yes, people classify it in ways that help them provide help for people who have it. But people who have it don't experience it that way. People who are describing it have to use a set of behaviors to define it because that's what they have to work with. People who have it describe it differently because that's how they experience the world.

People with autism describe their experiences very differently than those who don't have it who use the outward things they see to describe it also. When I read what Temple Grandin has to say about how she experiences her world, it is very different from the way a professional will describe autism. And what she says about how she experiences things is where I got my belief that ADD is a little sister to autism, because I experience many of the things that she does, although my overall experience is very different.

People shouldn't think that the professionals' descriptions of these disorders in any way helps people to understand what it is like to live with them. They don't.