Criteria for the diagnosis of psychosis in a patient with PD:
(1) presence of Parkinson's disease
(2) presence of 2 or more characteristic symptoms of psychosis (see below)
(3) The onset of Parkinson's Disease precedes the onset of the psychotic symptoms.
(4) The psychotic symptoms persist for over 1 month (may be either recurrent or continuous)
(5) The psychotic symptoms cannot be explained by another diagnosis (see below).
Psychotic symptoms include:
(1) false sense of presence (belief that someone is present when no one is)
(2) delusions
(3) illusions
(4) hallucinations
Conditions to exclude:
(1) general medical condition causing delirium
(2) dementia with Lewy bodies
(3) schizophrenia or schizoaffective disorder
(4) delusional disorder
(5) mood disorder with psychotic features
Additional conditions to note:
(1) presence or absence of insight
(2) presence or absence of dementia
(3) any therapy for Parkinson's disease
