Amphetamine availability predicts amphetamine-related mental health admissions: A time series analysis

Amphetamine use and availability have increased in Australia and there are concerns that this has led to more frequent hospital admissions with amphetamine-related psychosis. This study examines whether amphetamine-related admissions to mental health units are more common at times of greater amphetamine availability.

We conducted an ecological study using aggregate crime and health service data for NSW, Australia, from January 2000 to March 2015. Amphetamine-related criminal incidents (arrests or cautions for possession or use) were used as an indirect measure of amphetamine availability. Semiparametric time series analysis was used to compare monthly arrest rates to monthly hospitalisation rates for (1) amphetamine abuse or dependence, (2) amphetamine-related psychosis and (3) any psychosis.

Amphetamine-related admissions to NSW mental health units have increased four- to fivefold since 2009 and comprised approximately 10% of all admissions to these units in early 2015. There was a significant association between arrests and amphetamine-related admissions. After adjustment for seasonal variation, this effect demonstrated a time lag of 1-2 months. There was no relationship between amphetamine arrests and overall admissions for psychosis.

Greater amphetamine availability significantly predicts admissions for amphetamine use disorders and amphetamine-related psychosis. Better treatment strategies are needed to break the nexus between drug availability and drug-related harm.