Increase in Purity to Price Ratio May Explain Increase in Methamphetamine Related Harms

Decreases in the price of methamphetamine along with an increase in purity may account for the recent increase in meth related harms in Victoria, according to a recent paper in Addiction. The paper looked at the purity and price of heroine and methamphetamine using data from offender interviews and drug seizures between 2009 – 2013 .


While the average purity of heroin seizures remained consistent and low, the average purity of powder and of crystal methamphetamine seizures increased from 12% [95% confidence interval (CI) = 10–14%] to 37% (95% CI = 20–54%) and 21% (95% CI = 18–23%) to 64% (95% CI = 60–68%), respectively. Crystal methamphetamine purity was bimodal, with observations generally less than 20% or greater than 70%. The average unadjusted price per gram for heroin decreased from $374 (95% CI = $367–381) to $294 (95% CI = $280–308), powder methamphetamine did not change significantly from $252 (95% CI = $233–271), and crystal methamphetamine increased substantially from $464 (95% CI = $416–511) in 2009 to $795 (95% CI = $737–853) in 2011. This increase was offset by an even greater increase in purity, meaning the average purity-adjusted price per gram declined. Furthermore, pure prices of both methamphetamine forms were similar, whereas their unadjusted prices were not. The pure price of heroin fluctuated with no ongoing trends.

Decreases in methamphetamine purity-adjusted price along with the bimodality of crystal methamphetamine purity may account for some of the recent increase in methamphetamine-related harm. For a given amount spent, methamphetamine purchase power has increased and the presence of extreme purity variations may challenge individuals’ control of consumption.


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