Longitudinal trajectories of polydrug use among adolescents: Two-year follow-up Martínez-Loredo, V. 1, De La Torre-Luque, A. 2, Grande- Gosende, A. 1, García-Perez, A. 1, & Fernández-Hermida, J.R. 1 1Addictive Behaviors Research Group. Department of Psychology. University of Oviedo, Spain 2Research Institute of Health Sciences, University of the Balearic Islands

Acknowledgements and Disclosure This work was supported by the Ministry of Health Ref. MSSSI-12-2013/131 and by a predoctoral grant from the Spanish Government Ref. BES-2015-073327 Conflict of interest: none

Introduction (I) The EMCDDA/PNSD estimates that… 48% of the adolescents had consumed alcohol during the last 30 days  67.65% Spain 21% of the adolescents had smoked cigarettes during the last 30 days  24.95% Spain 16% of the adolescents had smoked cannabis at least once in their lifetime 27,43% Spain

Introduction (II) Age of onset of the main substances is between 13 and 15 years old  early substance use as risk factor for SUD Some individuals develop risk patterns of use (substance abuse, binge drinking, polydrug use)  leads to problems, risk behaviors or dependence Few studies have explored differential patterns of substance involvement among adolescents (mainly cross-sectional studies focused on single substances) To identify risk trajectories of substance use is an important outcome for prevention and treatment Goal  To empirically characterize patterns of polydrug use among a big sample of Spanish community-based adolescents

Sociodemographic characteristics Method (I) Participants 1,612 adolescents randomly recruited from 22 secondary schools in the Principality of Asturias and Valencia (Spain). Sociodemographic characteristics Gender 54.5% males Mean age 13.06 years (SD = 0.52) Country of birth 89.1% Spain Wave 1 13 years old Wave 2 14 years old Wave 3 15 years old 2013-14 2014-15 2015-16 ≈12.71 % attrition

Variables & Instruments Method (II) Variables & Instruments Substance use Frequency of previous year alcohol, tobacco and cannabis use were assessed using items from the European School Survey Project on Alcohol and Drugs (ESPAD) Age at first drink (AFD) Heavy drinking Frequency of intoxication episodes within the past month Presence of alcohol-related problems using the Spanish validation of the Rutgers Alcohol Problem Index (RAPI) (López-Núñez et al. 2012) (α = .88-.92)

Method (III) Data Analysis Growth Mixture Modelling (LCMM) based on ML Goodness of fit criteria Sample-adjusted Bayesian Information Criterion (SABIC) Akaike Information Criterion (AIC) Best growth solution defined by The smallest SABIC & AIC Means of posterior probabilities in each class higher than .80 Covering at least 5% of participants in each class

Results (I) T1 T2 T3 Tobacco use 268 (17.20) 281 (17.90) 448 (18.60) N (%) T2 T3 Tobacco use 268 (17.20) 281 (17.90)  448 (18.60)  None 1,297 (82.9) 1,284 (82.0) 1,117 (71.4) 1-2 times 50 (3.2) 82 (5.2) 124 (7.9) 3 or more times 218 (14.0) 199 (12.7) 324 (10.7) Alcohol use 708 (45.20) 833 (53.20) 1,126 (72.1) 857 (54.8) 732 (46.8) 439 (28.1) 317 (20.30) 328 (21.0) 303 (19.4) 391 (24.9) 505 (32.2) 823 (52.7) Cannabis use 98 (6.30) 179 (11.50) 317 (20.60) 1,467 (93.7) 1,386 (88.6) 1,248 (79.7) 39 (2.5) 75 (4.8) 110 (7.0) 59 (3.8) 104 (6.7) 207 (13.6) Intoxication episodes 65 (4.20) 113 (7.30) 238 (15.30) 1,500 (95.8) 1,452 (92.8) 1,327 (84.8) 43 (2.7) 84 (5.4) 170 (10.9) 22 (1.5) 29 (1.8) 68 (4.4) RAPI 0.57 (3.47) 1.11 (4.38) 1.94 (5.58)

Results (I) 20.5% 61.3% 14.45% 14.90% T1 T2 T3 Tobacco use 268 (17.20) N (%) T2 T3 Tobacco use 268 (17.20) 281 (17.90)  448 (18.60)  None 1,297 (82.9) 1,284 (82.0) 1,117 (71.4) 1-2 times 50 (3.2) 82 (5.2) 124 (7.9) 3 or more times 218 (14.0) 199 (12.7) 324 (10.7) Alcohol use 708 (45.20) 833 (53.20) 1,126 (72.1) 857 (54.8) 732 (46.8) 439 (28.1) 317 (20.30) 328 (21.0) 303 (19.4) 391 (24.9) 505 (32.2) 823 (52.7) Cannabis use 98 (6.30) 179 (11.50) 317 (20.60) 1,467 (93.7) 1,386 (88.6) 1,248 (79.7) 39 (2.5) 75 (4.8) 110 (7.0) 59 (3.8) 104 (6.7) 207 (13.6) Intoxication episodes 65 (4.20) 113 (7.30) 238 (15.30) 1,500 (95.8) 1,452 (92.8) 1,327 (84.8) 43 (2.7) 84 (5.4) 170 (10.9) 22 (1.5) 29 (1.8) 68 (4.4) RAPI 0.57 (3.47) 1.11 (4.38) 1.94 (5.58) 20.5% 61.3% 14.45% 14.90%

Results (II) First trajectory (black line, 8.69% participants): early use and steep increase later on

Results (II) Second trajectory (dashed line, 81.28% participants): stable low alcohol use (normative substance use) without any other substance use

Results (IV) Third trajectory (grey line, 10.03% participants): low substance use up to T2 and an escalation in substance involvement between T2 and T3

Discussion Early users are mainly smokers: increasing prevalence of tobacco and cannabis co-use (Webster, 2014)  preventive efforts for increasing the risk perception of cannabis A large low-risk class of moderately alcohol users & no users was also previously reported (Dierker et al., 2007; Khurana et al., 2015; Lamont et al., 2014; Lanza et al., 2010; Shin, 2012): similarity in response patterns and absence of associated risks (Cranford, McCabe, & Boyd, 2013; Lamont et al., 2014; Shin, Hong, & Hazen, 2010) The telescoping trajectory is a novel finding: to focus on specific patterns of use instead of isolated general indexes (i.e. prevalences)

Conclusions First study finding different polydrug trajectories among early adolescents  three main trajectories: early users, normative users, telescopers Special attention to the telescoping trajectory  finding associated specific risk factors is encouraged The AFD did not differ between polydrug trajectories (too fuzzy measure)

Addictive Behaviors Research Group Department of Psychology THANK YOU OBRIGADO Martinezlvictor@uniovi.es loredo@cop.es Addictive Behaviors Research Group Department of Psychology University of Oviedo grupoca@uniovi.es