S.M.
You need to call your insurance NOW and find out what diagnoses are covered for mental health benefits. I work for a mental health insurance company, and I know that alot of them out there DO NOT cover services for PDD or ANY of the Autism spectrum disorders. The mental health company says, that's medical, call your medical insurance for coverage, and the medical one says, that's psych, call your mental health provider. Basically, no one has been able to agree where or how services should be covered, so alot of times they just aren't.
Good Luck.