narcolepsy
"Had no life at all except pain and overwhelming fatigue for 10 years.  Visited many doctors with no help at all. I am a scientist began tracking medicines that were in the pipeline - came across Provigil, looked like it was the one for me.  When it became available I was first in line.  changed my life completely; I was normal again; I could produce again and did to a stunning degree. 3 weeks ago, after 8 years, Provigil completely stopped working. I know all the obvious reasons but makes no sense, I am again existing with no quality to go forward. Am manically changing to Adderall while I try to figure this out."