Tracking the availability of drugs in New Zealand: implications for policy response.

• Author: Wilkins, Chris
• Position: Report

Abstract

Drug use imposes a range of health and social costs on New Zealand society. Measures of the availability of drugs are important for understanding levels of drug use and changes in drug use over time. Policy makers can directly affect levels of drug availability through a range of policy tools, including age restrictions, vendor regulation, varying levels of enforcement, and changing the legal classification of drug types. This paper presents population-level data on the current availability, and recent change in availability, of the 11 most commonly used drug types in New Zealand. Alcohol, tobacco and BZP/TFMPP party pills (i.e. the legally available drugs) were found to be by far the easiest drug types to obtain. Cannabis was the most easily available illegal drug, although it was much less available than the legal drugs. Cannabis was assessed by last-year users to be relatively more difficult to obtain in 2006 compared to 1998, 2001 and 2003. Amphetamine was also assessed to be relatively more difficult to obtain in 2006 compared to 2001. The decline in the availability of amphetamine occurred during a period after 2001 of sustained focus by drug enforcement agencies on disrupting clandestine methamphetamine manufacture and supply. A fall in the availability of nitrous oxide in 2006 followed a tightening of the rules concerning its sale by the Ministry of Health. Our findings suggest that policy makers can negatively affect the availability of a drug and, in turn, its level of use, with effective policy interventions.

INTRODUCTION

Drug use imposes a range of health and social costs on New Zealand, including death, illness, mental health problems, injuries from accidents, violence, property crime, family and relationship breakdown, and child neglect (Ministerial Committee on Drug Policy 2007). Much of the monitoring of drug use has traditionally involved measures of the prevalence of use of a drug type within the population, and how the population prevalence changes over time (see Black and Casswell 1993, Field and Casswell 1999, SHORE 2004, Wilkins, Casswell, et al. 2002). However, measures of the availability of a drug type can also provide valuable information that can be used to inform the development of effective drug policy.

Measures of drug availability are of particular interest to policy makers because drug policy can directly affect levels of drug availability through a range of policy tools, such as purchase age restrictions, product taxation, vendor licensing, hours of trading, vendor density, advertising restrictions, increasing enforcement, and changes to a drug's legal classification (see Babor et al. 2003, Ministry of Health 2004). The level of use of a drug is generally closely related to its availability: greater availability can lead to more convenient purchase, which in turn can lead to increased use. Rising availability of a drug type can often be a forewarning of future increases in the use of a drug. In the case of illegal drugs, increasing levels of availability can indicate increased dealing, smuggling and clandestine manufacture, or more open public selling of illegal drugs, such as from street drug markets. Measures of drug availability can therefore assist in understanding changes in use, and consequently inform policy responses (Wilkins, Bhatta, et al. 2002, Wilkins et al. 2006).

The concept of drug availability has been most widely used in relation to legal drugs, such as alcohol and tobacco (Ministry of Health 2004, World Health Assembly 1999). In the alcohol literature, availability is most often used to refer to the "accessibility or convenience" of purchasing alcohol (Babor et al. 2003:117). In the illegal drugs literature, availability is discussed under the term "search costs", which refers to the time buyers must spend finding sellers and completing transactions in the illegal drugs market (see Kleiman 1992, Moore 1977). In this paper we use the term "availability" in its widest sense, meaning the ease or difficulty of physically obtaining a drug.

The aim of this paper is to present data on the current availability, and change in availability, of the 11 most commonly used drug types in New Zealand. Longer-term trends in the availability of cannabis, amphetamine and ecstasy are also examined. The final section of the paper places the findings in the context of recent drug policy in New Zealand.

METHOD

National household surveying of drug use was conducted in New Zealand in 1998, 2001, 2003 and 2006 using the same Computer Assisted Telephone Interview (CATI) survey methodology (see Field and Casswell 1999, Wilkins, Casswell, et al. 2002, SHORE 2004, Wilkins, Sweetsur, et al. 2006). Respondents were informed that the study was being conducted on behalf of the Ministry of Health and that everything they said would be confidential. The age range of the respective survey waves were truncated to those aged 1545 years old for the purposes of our analysis to allow valid comparisons back to the 1998 survey. The general population samples of each survey wave were compared.

Those respondents who reported using a drug type in the past 12 months were asked to describe the drugs current availability using a four-point scale (i.e. very easy, easy, difficult, very difficult), and to indicate whether the drugs availability had changed in the past 12 months using a three-point scale (i.e. easier, same, harder). (2) In the 2006 survey wave, respondents were asked to describe the current availability and change in availability of a range of drug types. The 1998 survey asked respondents about the change in the availability of cannabis compared to a year ago, and this question was asked in the subsequent 2001, 2003 and 2006 survey waves. In the 2001 survey, respondents were asked about the change in the availability of amphetamine and ecstasy (MDMA) compared to a year ago, and these questions were included in all subsequent survey waves. The respective sample sizes for each survey wave were: 5,475 in 1998, 5,504 in 2001, 3,042 in 2003...