One Flew Over The Cuckoo's Nest - the "Fog"

The fog that occurs frequently in the novel One Flew Over the Cuckoo's Nest is considered to be blinding, but also random. The fog according to Chief  occurs after shock therapy, but the reader never really observes anyone else having the same effect. To add on, the setting of the story is an insane asylum, so who is to say Chief isn't the one actually making it up. Perhaps it isn't only Chief though, what if it were just side effects to the daily medicine (drugs) they have to take?

Now let's analyze Chief Bromden, and why he's in the asylum. Cheif Bromden shows certain signs including hostility, paranoia and delusions, social isolation, and lack of interest in personal hygiene. These are all signs of a well known mental disorder called schizophrenia. Alike most patients in the hospital Chief Bromden would need his daily amount of medicine to take care of most problems that schizophrenia contain.

When patients in a mental hospital are misbehaving and hurting others, they must be dosed with something to keep them calm. Perhaps what they treat them with is a drug that blinds them, or "fogs" them from seeing much. This stategy is somewhat like that of an alligator hunter, the hunter throws a towel or a bag over the head of the alligator to keep it from hurting anyone.
Alike the alligator Chief was reacting violently to the black boys shaving him. Though little did he know, that during the adrenaline rush he accessed from fighting back, he had been drugged with what he claimed was a "fog machine". So the only inference that would most likely uncover what the fog is, would be the drugs.