Ascertaining substance use prevalence amongst upper-level high-school adolescents and comparing these figures with those from 1996 and 1997.2,291 randomly sampled high-school adolescents participated in a cross-sectional survey about legal and illegal substance abuse.Mean adolescent age was 15,9 (1,09 SD); 53,9 % of the sample was female. The use of several substances grew from 1996/1997 to 2004, i.e. marihuana (1,5 % to 4,4 %), crack (0,.4 % to 1,2 %), inhalants (0,1 % to 1,2 %), stimulants (0,7 % to 1,9 %), and tranquilisers (2,0 % to 3,1 %). Similar figures were found for weekly alcohol use to the point of getting drunk (6,5 % to 7,7 %). Annual MDA use was 2,5 % (a substance not studied in 1996/1997).Inhalant and tranquiliser consumption amongst high-school adolescents has increased dramatically during the last few years. MDA consumption has reached a significant percentage.