[Illicit substances use by Portuguese adolescents].

OBJECTIVE To describe the prevalence of illicit drug consumption among adolescents and the motives that led these adolescents to try them. METHODS Cross-sectional study with 2,499 adolescents aged 17 years, based on a cohort called EPITeen, which was started in 2003/2004 with adolescents born in 1990 who studied in public and private schools of the city of Porto, Portugal. A new assessment was carried out in 2007/2008: 1,716 adolescents (79.5%) were recovered and 783 new participants were evaluated. Information about social and demographic characteristics, family and personal history of diseases and behaviours were obtained through self-administered structured questionnaires. The chi-square test was used to test the associations. The statistical analysis was performed in the program SPSS® version 17. RESULTS Of the adolescents, 14.6% had tried drugs at least once in their lives. The most tried illicit drug was cannabis (12.5%), followed by alcohol together with cannabis (5.5%) and tranquilizers (1.7%). The most cited reason for trying drugs was curiosity (77.5%). Friends were the most frequently cited form of obtaining drugs and the school was seen by 24.2% of the adolescents as a place where it was possible to buy cannabis. CONCLUSIONS The results support the need to intervene at an early age and suggest that this intervention should be integrated with strategies targeted at other risk behaviors, particularly in schools.