Weird Psychiatric Disorder Day

This morning's brief movie capsule didn't explain either delusional parasitosis or folie à deux. Wikipedia says that

Delusional parasitosis is a form of psychosis in which sufferers hold a delusional belief they are infested with parasites.

Mind Hacks has the best description of this bizarre condition in The curious case of Morgellons disease:

Morgellons is claimed to be a new form of skin disease by its sufferers but has been largely ignored by the medical community and some have claimed it is, in reality, a psychotic syndrome akin to delusional parasitosis.

Michael Shannon's character in Bug suffered from delusions that far exceeded mere aphid infestation, and he easily persuaded his drunk, drug-using, desperate and lonely new girlfriend (Ashley Judd) that the tiny bugs were real, so that she spiraled down with him in a folie à deux:

(literally, "a madness shared by two") is a rare psychiatric syndrome in which a symptom of psychosis (particularly a paranoid or delusional belief) is transmitted from one individual to another. ... Recent psychiatric classifications refer to the syndrome as shared psychotic disorder (DSM-IV) (297.3) and induced delusional disorder (folie à deux) (F.24) in the ICD-10, although the research literature largely uses the original name.

The director was William Friedkin, of The Exorcist fame, so be prepared for some over-the-top gory scenes of self-mutilation and self-dentistry (as well as some dark humor and romantic love).


Bug (2006) - Brian F. O'Byrne, Michael Shannon