Ha ha, I was wondering because it didn't seem like he was paranoid or catatonic (those are the two I remember and I'm too lazy to reach down and pick up my BioPsych textbook). I'm pretty anal about how psychological orders and their treatment are portrayed.
Author's response
Keep in mind he's pretty heavily medicated by some sort of unnamed 1920's antipsychotic that turns his tongue blue. If you're gonna gun for a plot hole, go for the medication. I'll try and work on his portrayal for later.