Abstract
To the Editor
Sara et al.’s (2015) meta-analysis found a high rate of stimulant use disorders among people with psychosis, suggesting that stimulants are likely to make a significant contribution to the overall burden of psychosis. However, as Sara et al. (2015) excluded studies that primarily focussed on samples of individuals with substance-induced psychosis, the contribution of stimulants to the overall burden of psychosis is likely to be greater, given consistent evidence that regular stimulant use can increase the risk of experiencing psychosis in a dose-dependent manner (McKetin et al., 2013). Despite growing concerns regarding increasing rates of stimulant use and related harms (especially methamphetamine [MA]) in Australia, as yet, few studies have quantified the impact of stimulant use on psychosis presentations to acute health systems.
We examined illicit drug involvement in Victorian ambulance attendances where patients presented with psychosis symptoms between January 2012 and August 2014 to characterise the acute harms associated with MA-related psychosis presentations. Data were extracted from the Ambo Project database. 1 Analysis of all ambulance attendances for psychosis over this period showed that stimulant drugs were more likely to be implicated in presentations of psychosis in comparison with all other illicit drugs combined. MA was the drug most commonly associated with drug-related psychosis, comprising 6.1% of all ambulance attendances for psychosis, and 93% of all stimulant-related psychosis presentations; 13.4% of MA-related psychosis presentations also involved cannabis use, a common co-morbidity highlighted by Sara et al. (2015).
Further analysis was undertaken to compare MA-related psychosis presentations to those where no drug use was reported (Table 1). A significantly higher proportion of MA-related psychosis presentations involved younger men, presenting in metropolitan outdoor areas, and involved police co-attendance, compared with non-drug-related attendances. In addition, significantly more individuals with non-drug-related psychosis had a self-reported past history of psychosis, and had presentations that involved self-harm.
Comparison of characteristics of Victorian ambulance presentations for psychosis symptoms by drug use, January 2012–August 2014.
Median length (mins) of attendance: time arrived at patient to time to clear the attendance.
p < 0.05.
These findings demonstrate that a proportion of individuals who use stimulants may develop transient psychotic symptoms that require intervention by acute health services. While previous studies have identified that the presenting symptoms of stimulant-related psychosis may be indistinguishable from non-drug-related psychosis (Hermens et al., 2009), these data do demonstrate a number of socio-demographic factors that differ between the two types of acute presentations.
Footnotes
Acknowledgements
The authors would like to acknowledge and kindly thank Ambulance Victoria and its paramedics for their entry of data used in this study.
Declaration of interest
Dan Lubman has received speaking honorarium from AstraZeneca and Janssen, as well as provided consultancy advice to Lundbeck.
Funding
This project is a collaborative project between Turning Point and Ambulance Victoria and is funded by the Victorian Department of Health and Human Services and Commonwealth Department of Health and Aging.