First cannabis use: does onset shift to younger ages? Findings from 1988 to 2003 from the Dutch National School Survey on Substance Use

Aims: To investigate the hypothesis that changes in cannabis prevalence among Dutch secondary school students (aged 12-17 years) were paralleled by shifts in the age of first cannabis use. Design and participants: Data were derived from five waves (1988, 1992, 1996, 1999 and 2003) of the Dutch National School Survey on Substance Use, a nationally representative cross-sectional study, with a total of 32 777 respondents. Measurements: Written questionnaires on cannabis, tobacco, alcohol, other drug use and socio-demographic and behavioural variables were administered in classroom settings. Findi... Mehr ...