“Vitamin C” = cocaine.
I have worked around, and clashed with two managers who had a thing for the nose candy. Both got fired. One had some really erratic behavior that was even noticed by the client, was drug tested, and out he went. The other was a belligerent power nut who tried getting in a fight with me - in the office - and found out I knew the local police chief (I knew the chief from when he was setting up a bicycle patrol. The manager got pulled over a few times). He later tried making his point physically to this one older wiry engineer (a former Israeli paratrooper, he finds out the hard way) and out he went.
Obama definitely looks like a user.
He isn't wiry at all. Just thin and weak-looking.
But if he is on coke, he handles it well. Most users I knew kept increasing their usage until there were visible and noticeably signs in their behavior.
While Obama seems like a dolt...he doesn't seem shaky or druggy (except his appearance).