This actually varies.
When I was diagnosed I had to go though many counseling sessions and be seen by a nurlogist and other cognitive behavioral psychologist.
It took around 5 months of the doctors and my mom, as well as my self to get everything sorted out.
I think this is the way to go....
However many times now you can see any doctor and tell them symptoms and they will diagnose you or refer you to a specialist who can and is able to prescribe those types of controlled substances.