RESEARCH REPORT doi:10.1111/j.1360-0443.2010.03068.x Mexico’s methamphetamine precursor chemical interventions: impacts on drug treatment admissionsadd_3068 1973..1983 James K. Cunningham1, Ietza Bojorquez2, Octavio Campollo3, Lon-Mu Liu4 & Jane Carlisle Maxwell5 Department of Family and Community Medicine,The University of Arizona,Tucson,AZ, USA1, Directorate General of Epidemiology, Ministry of Health, Mexico City, Mexico2, Center of Studies on Alcohol and Addictions, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico3, Public Economics Research Center, College of Social Sciences, National Taiwan University,Taipei,Taiwan4 and Center for Social and Behavioral Research,The University of Texas,Austin,TX, USA5 ABSTRACT Aims To help counter problems related to methamphetamine, Mexico has implemented interventions targeting pseudoephedrine and ephedrine, the precursor chemicals commonly used in the drug’s synthesis. This study examines whether the interventions impacted methamphetamine treatment admissions—an indicator of methamphetamine consequences. Design Quasi-experiment: autoregressive integrated moving average (ARIMA)-based intervention time–series analysis. Interventions: precursor chemical restrictions implemented beginning November 2005; major rogue precursor chemical company closed (including possibly the largest single drug-cash seizure in history) March 2007; precursor chemicals banned from Mexico (North America’s first precursor ban) August 2008. Settings Mexico and Texas (1996–2008). Measurements Monthly treatment admissions for methamphetamine (intervention series) and cocaine, heroin and alcohol (quasi-control series). Findings The precursor restriction was associated with temporary methamphetamine admissions decreases of 12% in Mexico and 11% in Texas. The company closure was associated with decreases of 56% in Mexico and 48% in Texas; these decreases generally remained to the end of the study period. Neither intervention was associated with significant changes in the Mexico or Texas quasi-control series. The analysis of Mexico’s ban was indeterminate due largely to a short post-ban series. Conclusions This study, one of the first quasi-experimental analyses of an illicit-drug policy in Mexico, indicates that the country’s precursor interventions were associated with positive impacts domestically and in one of the Unites States’ most populous states—Texas. These interventions, coupled with previous US and Canadian interventions, amount to a new, relatively cohesive level of methamphetamine precursor control across North America’s largest nations, raising the possibility that the impacts found here could continue for an extended period. Keywords Methamphetamine, Mexico, Texas, precursor chemicals, intervention time series analysis, treatment admissions. Correspondence to: James K. Cunningham, Department of Family and Community Medicine, The University of Arizona, 1450 N. Cherry Avenue, Tucson, AZ 85719, USA. E-mail: [email protected] Submitted 21 April 2009; initial review completed 29 June 2009; final version accepted 15 March 2010 INTRODUCTION suppressing production of and thus problems attendant to the drug. This study examines whether these interven- Mexico has become a principal producer of methamphet- tions impacted methamphetamine treatment admissions, amine in North America [1]. Possibly in association, an indicator of methamphetamine consequences [9,10]. methamphetamine abuse in Mexico has increased in Following concerns about methamphetamine, Mexico recent years, a striking development given that the coun- conducted a study comparing legitimate need for meth- try’s drug consumption historically has been low and amphetamine precursor chemicals to actual import relatively stable [2–7]. In light of this, Mexico’s federal levels, and concluded that imports were excessive government has targeted the precursor chemicals [11–13]. In response, Mexico reduced its pseudoephe- used commonly in methamphetamine synthesis— drine imports from 132 826 kg in 2005 to 45 524 kg pseudoephedrine and ephedrine [8]—with the goal of in 2006 [12]. Monthly import data show that this © 2010 The Authors, Addiction © 2010 Society for the Study of Addiction Addiction, 105, 1973–1983 1974 James K. Cunningham et al. reduction, which was thought to have placed imports methamphetamine-related hospitalizations in Califor- roughly in line with legitimate need [11], was achieved by nia, Arizona and Nevada [25]; and (v) methamphet- consistently limiting imports to a range of 150–7000 kg amine treatment admissions in California [10]. This last per month, a pattern which began in November 2005 finding suggests that if precursor controls in Mexico [14]. In comparison, during the preceding period of should prove effective, the country’s methamphetamine January–October 2005, imports ranged from 475– treatment admissions would also decrease. That said, 31 000 kg per month. the generalizability of US precursor control findings to In February 2006, Mexico expanded its precursor other countries is an open question, as recent research restrictions by requiring that (i) pseudoephedrine dis- indicates that precursor controls in Canada were tributors register customers in a federal computerized not associated with decreases in that country’s data system; (ii) pharmacies limit pseudoephedrine methamphetamine-related hospitalizations [26]. product sales to Յ60 mg per product per day; (iii) diver- This study uses autoregressive integrated moving sion, loss, theft, wastage or extraordinary sale of pseu- average (ARIMA)-based intervention time–series analy- doephedrine products be reported immediately; (iv) sis (a quasi-experimental procedure) to examine the monthly electronic input/output records of pseudoephe- possible impact of Mexico’s precursor chemical interven- drine sales be submitted to the government; and (v) tions on monthly methamphetamine treatment admis- federal officials, upon request, be given immediate access sions for the nation as a whole (1996–2008). Cocaine, to records created in the past year [15]. In an update, heroin and alcohol treatment admissions in Mexico are prescriptions were required to obtain any pseudoephe- used as quasi-control series. Methamphetamine use in drine product in a pharmacy beginning September 2007 Mexico is concentrated primarily in states within the [16,17]. northwest region of the country, and in states within the In March 2007, the Mexican government searched central region ([3] cf. [27,28]). Time–series (without the Mexico City home of Zhenli Ye Gon, head of Unimed ARIMA analyses) are presented for these two groups of Pharm Chem de Mexico—a commercial chemical states. company—and seized more than $200 million cash in Drugs produced/transported in Mexico are often des- US currency plus additional cash in other currencies: tined for US consumption [29], suggesting that Mexico’s possibly the largest single drug-cash seizure in history controls could also impact the United States. To consider [18,19]. Officials accusedYe Gon of using the company to this issue, methamphetamine, cocaine, heroin and illicitly import 60+ tons of pseudoephedrine [18]. Follow- alcohol treatment admissions in Texas are examined ing an international manhunt, Ye Gon was arrested in using ARIMA analysis. Texas is one of the most populous July 2007 [20]. The ability of Ye Gon and Unimed Pharm US states; its Mexico border is the longest of any US state Chem de Mexico to continue massive pseudoephedrine (1248 miles), and the bulk of the methamphetamine in smuggling (assuming the charges are accurate) was Texas reportedly originates in Mexico [30–33]. probably compromised significantly, if not ended, when US drug treatment admissions are often coerced by Ye Gon’s home was searched and the cash was seized. government legal/enforcement systems (e.g. courts), and Subsequent to the Ye Gon investigation, in September such admissions can reflect government administrative 2007 the Mexican government filed 41 criminal com- priorities more than drug-market dynamics [10]. In con- plaints involving multiple companies for the falsification trast, voluntary admissions (barring changes in treat- of 161 import permits related to pseudoephedrine and ment availability) are thought to better indicate actual other health supplies [21]. treatment demand, and thus drug-market dynamics In August 2008, Mexico banned pseudoephedrine [10,34]. Consistent with this, research has found that and ephedrine from the country, excepting as needed in voluntary methamphetamine treatment admissions in federally approved research, surveillance and toxicologi- California changed sharply in association with precursor cal analysis [22]. In so doing, Mexico superseded its controls, while coerced admissions had little such asso- prior import and pharmaceutical restrictions. It also ciation [10]. Unlike the United States, Mexico’s metham- became the first North American country to ban these phetamine treatment admissions are essentially chemicals. voluntary. For example, in 2006, only 4% of Mexico’s Mexico’s precursor control efforts have received methamphetamine admissions were associated with law little study. There has been research on US precursor enforcement [35], limiting the likelihood of a practical controls, however, and it indicates they were associated confounding effect. However, a substantial percentage of with decreases in (i) methamphetamine-related arrests Texas’ methamphetamine treatment admissions are in California [23]; (ii) methamphetamine purity in referred