Drug-induced psychosis in Parkinson disease: phenomenology and correlations among psychosis rating instruments.
OBJECTIVE
To describe further the phenomenology of drug-induced psychosis (DIP) in patients with Parkinson disease (PD) and assess which items on two common psychosis rating instruments-the Brief Psychiatric Rating Scale (BPRS) and the Neuropsychiatric Inventory (NPI)-are the best measure of DIP by comparing them with the Clinical Global Impression Scale (CGIS).


METHODS
Baseline data from two placebo-controlled, double-blind studies of olanzapine in PD patients with DIP were collected and analyzed.


RESULTS
A total of 157 of 160 patients had hallucinations, with visual hallucinations being the most common (97% of subjects), followed by auditory (48%), tactile (23%), and olfactory (16%). Seventy-six percent of subjects experienced delusions, and all types of delusions occurred with relatively equal frequency. The CGIS correlated with suspiciousness, hallucinatory behavior, unusual thought content, and hostility on the BPRS; and delusions, hallucinations, agitation, aberrant motor behavior, and sleep on the NPI.


CONCLUSIONS
Nonvisual hallucinations and delusions may occur more frequently in DIP than previously thought. These symptoms, plus agitation and hostility, may ultimately be the best measure of DIP in patients with PD.
Chou
Kelvin L
KL
Department of Clinical Neurosciences, Brown Medical School, Providence, Rhode Island, USA. Kelvin_Chou@brown.edu
Messing
Susan
S
Oakes
David
D
Feldman
Peter D
PD
Breier
Alan
A
Friedman
Joseph H
JH
D000368:Aged; D003702:Delusions / Q000209:etiology / Q000523:psychology; D004311:Double-Blind Method; D005260:Female; D006212:Hallucinations / Q000209:etiology / Q000523:psychology; D006801:Humans; D008297:Male; D010300:Parkinson Disease / Q000150:complications* / Q000523:psychology; D011569:Psychiatric Status Rating Scales; D011605:Psychoses, Substance-Induced / Q000150:complications* / Q000175:diagnosis / Q000523:psychology