Illegal substance use among Italian high school students: trends over 11 years (1999-2009).
PurposeTo monitor changes in habits in drug use among Italian high school students.MethodsCross-sectional European School Survey Project on Alcohol and Other Drugs (ESPAD) carried out in Italy annually for 11 years (1999-2009) with representative samples of youth attending high school.The sample size considered ranges from 15,752 to 41,365 students