Analysis of illicit stimulant use triangulating wastewater, general population survey and web survey data.

Background: We analysed illicit stimulant use in Finland by comparing three separate datasets collected at the same time. Methods: The data used were wastewater analysis (2014 and 2018), population-based drug surveys (2014 and 2018) and European Web Survey on Drugs (2018, Finnish data). Proportions, prevalence levels and trends of stimulant use as well as their consumption were measured. Factors associated with stimulant use were assessed for past-year stimulant or amphetamine use as an outcome measure in regression analyses. Results: Both population-based drug survey and wastewater data showed that stimulant use has increased in Finland between 2014 and 2018. Disadvantaged socio-demographic background and other substance use were associated with past-year stimulant use, with no geographical variation in Finland. The socio-demographics of those reporting amphetamine use differed between population-based drug survey and web survey. In the web survey, infrequent and occasional users of amphetamine were quite alike, whereas frequent users were more likely to be unemployed or use injection as the route of administration. Conclusion: Analysis of three different data revealed findings that would have been missed and conclusions that could not have been made by using only one dataset. Putting findings from different methods into dialogue raises new questions and opens new interpretations. This analysis emphasises the importance of the prevention of frequent use and associated harm, as well as the impact of versatile drug treatment and harm reduction services on it.