Citation

Cunningham JK, Liu LM, Callaghan RC. Addiction 2009; 104(3): 441-453.

Copyright

(Copyright © 2009, John Wiley and Sons)

DOI

10.1111/j.1360-0443.2008.02458.x

PMID

unavailable

Abstract

Aims Reducing drug purity is a major, but largely unstudied, goal of drug suppression. This study examines whether US methamphetamine purity was impacted by the suppression policy of US and Canadian precursor chemical regulation.

Design Autoregressive integrated moving average (ARIMA)‐intervention time–series analysis.

Setting Continental United States and Hawaii (1985–May 2005).

Interventions US federal regulations targeting precursors, ephedrine and pseudoephedrine, in forms used by large‐scale producers were implemented in November 1989, August 1995 and October 1997. US regulations targeting precursors in forms used by small‐scale producers (e.g. over‐the‐counter medications) were implemented in October 1996 and October 2001. Canada implemented federal precursor regulations in January 2003 and July 2003 and an essential chemical (e.g. acetone) regulation in January 2004.

Measurements Monthly median methamphetamine purity series.

Findings US regulations targeting large‐scale producers were associated with purity declines of 16–67 points; those targeting small‐scale producers had little or no impact. Canada's precursor regulations were associated with purity increases of 13–15 points, while its essential chemical regulation was associated with a 13‐point decrease. Hawaii's purity was consistently high, and appeared to vary little with the 1990s/2000s regulations.

Conclusions US precursor regulations targeting large‐scale producers were associated with substantial decreases in continental US methamphetamine purity, while regulations targeting over‐the‐counter medications had little or no impact. Canada's essential chemical regulation was also associated with a decrease in continental US purity. However, Canada's precursor regulations were associated with purity increases: these regulations may have impacted primarily producers of lower‐quality methamphetamine, leaving higher‐purity methamphetamine on the market by default. Hawaii's well‐known preference for ‘ice’ (high‐purity methamphetamine) may have helped to constrain purity there to a high, attenuated range, possibly limiting its sensitivity to precursor regulation.