The risk of psychotic symptoms associated with recreational methamphetamine use.
OBJECTIVE
To determine whether recreational methamphetamine use is associated with an increased risk of psychotic symptoms.


METHODS
A cross-sectional survey of 157 people attending dance events in Sydney, Australia. Participants were assessed for psychotic symptoms in the past year using items from the Psychosis Screen. Participants with and without psychotic symptoms were compared on methamphetamine use, polydrug use and other demographic factors. An ordinal logistic regression was used to determine the probability of psychotic symptoms by methamphetamine use and level of polydrug use.


RESULTS
Psychotic symptoms in the past year were predicted by methamphetamine use and heavier polydrug use in the past year, and a history of a psychotic disorder (schizophrenia, schizoaffective or bipolar affective disorder). After removing participants with a history of a psychotic disorder (n = 16) and adjusting for polydrug use, methamphetamine use increased the probability of two or more psychotic symptoms (indicative of psychosis risk) from 9% to 21%. There was a non-significant increase in the risk of psychotic symptoms with higher levels of polydrug use. Methamphetamine use was typically monthly or less often (83%), and most users described their use as recreational (85%).


CONCLUSIONS
Within the context of polydrug use, recreational methamphetamine use is associated with a twofold to threefold increase in the probability of psychotic symptoms.
McKetin
Rebecca
R
National Drug and Alcohol Research Centre, University of New South Wales, Sydney, NSW 2052, Australia. r.mcketin@unsw.edu.au
Hickey
Karina
K
Devlin
Kristina
K
Lawrence
Kerri
K
D000293:Adolescent; D000328:Adult; D019969:Amphetamine-Related Disorders / Q000453:epidemiology / Q000209:etiology / Q000523:psychology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D013287:Illicit Drugs / Q000506:poisoning*; D008297:Male; D008694:Methamphetamine / Q000506:poisoning*; D011618:Psychotic Disorders / Q000453:epidemiology / Q000209:etiology / Q000523:psychology*; D012307:Risk Factors; D055815:Young Adult
D013287:Illicit Drugs; D008694:Methamphetamine