Internalizing and externalizing behavior problems and substance use in adolescence

This study investigated the relationship between externalizing behavior problems (EBP), internalizing behavior problems (IBP), and combined externalizing/internalizing behavior problems (EIBP) in early adolescence (11 years) and substance use (alcohol, tobacco, and illegal drugs) at 15 years, using data from the 1993 Pelotas (Brazil) birth cohort. Behavior problems were assessed with the Strengths and Difficulties Questionnaire (SDQ), applied to mothers when their children were 15 years old. Substance use was assessed with a self-applied confidential questionnaire for the adolescent. The association between behavior problems and substance use was analyzed with Poisson regression with robust adjustment of variance. After adjusting for confounding, adolescents with EBP showed higher risk of alcohol abuse (RR = 1.74, 95%C1: 1.21; 2.50) and experimentation (RR = 1.78, 95%CI: 1.42; 2,23) and tobacco use in the previous 30 days (RR = 2.38, 95%CI: 1.64; 3.45). Adolescents with IBP showed greater risk of having tried tobacco (RR = 1.54, 95%CI: 1.24 L 93) and of having used tobacco products in the previous 30 days (RR = 1.92, 95%CI: 1.31; 2.83). Adolescents with EIBP showed greater risk of trying (RR = 2.24, 95%CI: 1.57; 3.21) and consuming tobacco products in the previous days (RR = 3.01, 95%CI: 1.63; 5.56), and lower risk of having tried alcohol at 15 years of age (RR = 0.72, 95%CI: 0..55; 0.94). Public health measures aimed at reducing behavior problems in early adolescence can help reduce tobacco and alcohol consumption at 15 years.