CONICET | Buscador de Institutos y Recursos Humanos

The age of alcohol drinking onset (DO) is a vulnerability factor for alcohol-related problems, including alcohol abuse and dependence. Less is known on the effects of an early DO on subsequent use of illegal substances. This study analyzed the impact of DO on current patterns of alcohol, tobacco, marihuana, stimulants and hallucinogensuse. Participants (n = 382; 35.9% men), aged 18-30 years old (Mean age = 22.83 ± 3.10), completed an online survey assessing lifetime, last year, and last month use of alcohol, tobacco, marihuana, stimulants (cocaine, free-base, cocaine, amphetamines), hallucinogens (ecstasies, LSD, mushrooms), and depressants (heroin and non-prescription tranquilizers) substances. The majority used alcohol (94%) in the previous year, followed by marihuana (59%) and tobacco (50%). Last year prevalence of hallucinogen, stimulants, and depressants were 23%, 12%, and 5%, respectively. We identified, via Latent Class Analysis, three patterns of substance use. Class 1 (n = 163, 43%) had a high probability of concurrent use of alcohol, tobacco and marihuana; Participants in Class 2 (n = 127, 33%) had an elevated probability of only consuming alcohol. Class 3 (n = 92, 24%), exhibited a high probability of using all substances (alcohol, tobacco, marihuana, stimulants,and hallucinogens). An ANOVA indicated earlier onset of alcohol drinking (F2,376 =11.31; p≤.001) in participants from classes 1 (Mean age of DO = 14.39 ± 1.58) and 3 (Mean age of DO = 14.02 ± 2.64), when compared with those of class 2 (Mean age of DO = 15.09 ± 2.99). These results meet the hypotheses of the gateway model, which postulates that early onset of use of alcohol increases the risk of subsequent use of illegal substances.