Who "diagnosed everything except PTSD and Depression"? - your PCP or a Neurologist; were they your docs or the insurance docs. If so, either one is behind the times with their knowledge base on Concussion/PCS, because the root causations of your problem sounds like concussion /pcs secondary to the whiplash of the mva, leading tothe PTSD and Depression..they only need to do research to find that there is literature out there to prove these connections...they need to read more current literature.

Anyway, you are being referred to Neuropsych which isa good step, so cudos to whomever; but your Psychiatrist needs to be replaced if he believes, truly that you are a 'faker' - is he an insurance doc? If so, it figures.

One thing : have you still got sick time/ vacation time available at work? And are you being threatened about work regulations about losing time? Then you need to go to HR and request FMLA paperwork and have your M.D.'s complete them for your problems, for "long term, intermmitent, time off" so you can use time as necessary for those days you need to miss or take parts of days, etc. with or even when you run out of available time . The answer to the question about when do they expect you to return to full duty is "Undetermined". It is a protection mechanism.

Also, ask your docs to make a listing of possible job limitations for possible work accomodations from your employer; to cover all bases.

These are just steps to take towards trying to work with your employer to keep working, in some fashion. Its up to them to accept or deny wanting to work with them.