Full length articleTypology of new psychoactive substance use among the general Australian population
Introduction
Over the past decade, the number and range of substances collectively referred to as ‘new psychoactive substances’ (NPS) has increased dramatically. NPS are defined by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) as substances which do not fall under international drug controls but which may pose a public health threat (European Monitoring Centre for Drugs and Drug Addiction, 2016b). However, there are a number of problems with this definition (e.g., mere psychoactivity is assumed to be a public health threat; Barratt et al., 2017), and in practicality the term ‘NPS’ has come to include drugs that have previously not been well-established in recreational drug markets, or that are not well documented. In 2016, over 600 NPS were being monitored by the European Union (European Monitoring Centre for Drugs and Drug Addiction, 2016a), of which 70% were detected in the past five years (European Monitoring Centre for Drugs and Drug Addiction, 2016b).
Despite the rapid growth of the NPS market, and associated concerns of widespread use, prevalence appears to be relatively low amongst adult general population samples (i.e., ≤1.2%; UK Government Home Office, 2017; Australian Institute of Health and Welfare, 2017; Palamar et al., 2015). The use of these substances is thought to be concentrated amongst existing illicit drug consumers (Moore et al., 2013; Sutherland et al., 2016), and other disadvantaged groups (e.g., homeless, prisoners, mentally ill, people who inject drugs) (European Monitoring Centre for Drugs and Drug Addiction, 2017b; Joseph et al., 2017; Manseau et al., 2017; Rácz et al., 2016; Tarján et al., 2017). Concerns remain, however, that ‘novice’ consumers may initiate NPS use, particularly given use of the internet as a means of supply. Indeed, the argument that NPS appeal to novice consumers has been used to advocate for their prohibition, regardless of their harm profile, on the premise of preventing normalisation of NPS use and transition into other illicit drug use (Intergovernmental Committee on Drugs, 2014).
Our ability to address such concerns is limited by the fact that the comparability of NPS consumers with other illicit drug consumers has not been properly explored. Moreover, it remains unclear whether there is a distinct group of exclusive NPS consumers (i.e., people who use NPS but no other illicit substances), or whether there are particular groups of illicit drug consumers that report elevated rates of NPS use. In order to examine these questions, data from samples where inclusion is not based on illicit substance use, and where people may be consuming a broad range of substances, are required. General population data provide an important opportunity to answer this research question, with latent class analysis (LCA) a particularly suitable method for investigating whether distinct subtypes or classes of NPS consumers exist.
In identifying NPS consumers, it is critical to explore their relative demographic and risk profile. Previous studies have shown that people who report NPS use are typically younger, more likely to be male, report higher levels of poly drug use, younger age of drug initiation, more problematic drug use (e.g., bingeing), and are more likely to report online purchasing behaviours relative to illicit drug consumers who do not use NPS (Bonar et al., 2014; Bruno et al., 2012; Lawn et al., 2014; Palamar, 2015; Palamar and Acosta, 2015,;Emmanuel and Attarad, 2006). However, these studies are generally based on samples of people who use illicit drugs, limiting their capacity to identify unique NPS groups (including people using NPS but no other illicit substances).
As such, this study uses data from a general population sample to:
- 1)
Examine the typology of Australian illicit drug consumers to determine if there is a distinct group of exclusive NPS consumers, and if not, determine which consumer ‘type’ is most likely to use NPS.
- 2)
Compare profiles across these subgroups, based on demographics and risk behaviours.
This information will improve our understanding of the profiles of NPS users, allowing for the development of more targeted harm reduction messages.
Section snippets
Study design and participants
This paper uses data from the 2013 National Drug Strategy Household Survey (NDSHS; for full protocol details, see Australian Institute of Health and Welfare, 2014). The NDSHS, conducted on a triennial basis, collects data from the Australian residential population, and employs a multistage stratified sampling methodology designed to provide a close-to-random sample to obtain data on drug and alcohol use in the Australian population over 14 years of age. In 2013, 23,855 respondents participated
Sample characteristics
Among the entire sample (n = 23,855), the most commonly used illicit substance was cannabis (10.2%), followed by ecstasy (2.5%), methamphetamine (2.1%), cocaine (2.1%), hallucinogens (1.3%), SCRA (1.2%), inhalants (0.8%), NPS (excluding SCRA; 0.4%), ketamine (0.3%), heroin (0.1%) and GHB (<0.1%). Non-medicinal pharmaceutical drug use in the preceding year was reported by 4.7% of the sample, with past-year alcohol use reported by the majority (78.3%) of the sample. Very few participants (0.07%
Discussion
We found that there was no distinct profile of exclusive SCRA or other NPS consumers, with very few participants (n = 16; 5.7% of NPS consumers) reporting sole use of these substances. Rather, SCRA and NPS consumers mostly fell into the amphetamine and cannabis consumer and polysubstance consumer groups, respectively, providing support for the argument that most NPS consumers use a range of other illicit substances.
Polysubstance consumers (the group most likely to use NPS) were found to be
Conclusions
This study found no distinct profile of exclusive NPS consumers; rather the probability of SCRA and other NPS use was highest among amphetamine and cannabis consumers and polysubstance consumers. These groups reported the highest rates of drug-related harms (i.e., trouble ceasing use) and drug-related risk behaviours, respectively, suggesting that the use of SCRA or other NPS could be indicative of patterns of problematic drug use. These findings suggest that there may not need to be
Funding
The National Drug Strategy Household Survey is funded and commissioned by the Australian Government Department of Health. The funding source played no role in the study design; in the analysis and interpretation of data; in the writing of the report; or in the decision to submit the paper for publication.
Contributors
This work was undertaken by the National Drug and Alcohol Research Centre in Australia. All authors contributed to the writing and review of the manuscript and have approved the final manuscript for submission.
Conflict of interest
Amy Peacock (APP1109366) and Monica Barratt (APP1070140) are supported by National Health and Medical Research Council Fellowships.
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