First use of multiple substances: Identification of meaningful patterns

Abstract

Context: Understanding the process through which adolescents and young adults are trying legal and illegal substances is a crucial point for the development of tailored prevention and treatment programs. However, patterns of substance first use can be very complex when multiple substances are considered, requiring reduction into a few meaningful number of categories.

Data: We used data from a survey on adolescent and young adult health conducted in 2002 in Switzerland. Answers from 2212 subjects aged 19 and 20 were included. The first consumption ever of 10 substances (tobacco, cannabis, medicine to get high, sniff (volatile substances, and inhalants), ecstasy, GHB, LSD, cocaine, methadone, and heroin) was considered for a grand total of 516 different patterns.

Methods: In a first step, automatic clustering was used to decrease the number of patterns to 50. Then, two groups of substance use experts, three social field workers, and three toxicologists and health professionals, were asked to reduce them into a maximum of 10 meaningful categories.

Results: Classifications obtained through our methodology are of practical interest by revealing associations invisible to purely automatic algorithms. The article includes a detailed analysis of both final classifications, and a discussion on the advantages and limitations of our approach.

Keywords:

• Substance first use
• patterns
• classification

Acknowledgments

This study was supported by contract 00.001721/2.24.02.-81 from the Swiss Federal Office of Public Health and the participating cantons. First of all, we would like to thank the three social field workers, P. Fontannaz, L. Vandel, J-F. Schlaeppi, and the three toxicologists and health professionals, T. Buclin, P. Stephan, and H. Burkhalter, whose classifications of patterns are at the basis of this research. We also thank the students who participated in the pilot study comparing the two types of graphical presentation of the patterns. The SMASH 2002 survey was run within a multicentre multidisciplinary group from the Institute for Social & Preventive Medicine in Lausanne (Véronique Addor, Chantal Diserens, André Jeannin, Guy van Melle, Pierre-André Michaud, Françoise Narring, and Joan-Carles Suris), Institute for Psychology, Psychology of Development and Developmental Disorders, University of Berne, Switzerland (Françoise Alsaker, Andrea Bütikofer, and Annemarie Tschumper), and the Sezione Sanitaria, Dipartimento della Sanità e della Socialità (Canton Ticino and Laura Inderwildi Bonivento).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.