Quantitative Assessment of High School Students' Poly-drug Use: Related Social Aspects and School Dropout

Introduction: Poly-drug use has increased in recent decades, especially in young drug-using groups. Classic epidemiological indicators of drug use, such as prevalence and incidence of users of specific substances, are not adequate as measures of the possible harms of poly-drug use. We applied poly-drug use indicators, based on substance-specific harm scores reported by van Amsterdam and Nutt in 2015, to data from high school student surveys, showing their usefulness in identifying high-risk drug consumption. Analysing the 'correlation' between high-risk drug use of high school students and school dropout allows the evaluation of adopted prevention policies and may suggest more suitable approaches. Methods: Each drug user is characterized by two specific scores: overall frequency of use of substances during the period of interest (FUS) and poly-drug use score (PDS). The poly-drug use score is a weighted average of the harm scores of the individual substances used multiplied by their respective frequencies of use. The PDS increases with the frequency of use, with the number of substances used, and with the specific harm scores of each substance. This indicator consists of two components, one representing the health harm score toward self and the other the social harm score toward others. Results: The indicators have been applied to sample data involving youth population, specifically the ESPAD®Italia survey data on high school students conducted annually in Italy. The trends of poly-drug use at different ages of students, 15-19 years, over time, and gender have been studied. The results have been linked to educational outcomes, early school leaving and social aspects, making it possible to assess present prevention interventions and suggest appropriate planning of future prevention interventions. Conclusion: Poly-drug use indicators allow a comprehensive quantitative evaluation of the risks of drug use. The analysis of the links between heavy use of drugs, school performance and dropout, and the social variables that influence them, shown in this work, suggests how best to plan secondary or indicative prevention interventions at school. The problem of including "new" NPS in analyses is also briefly discussed.