Abstract
BACKGROUND AND AIMS: Substance use poses a considerable challenge with adverse consequences on physical and psychological well-being, and societal dynamics, particularly among adolescents and young adults. This cross-sectional study aimed to investigate substance use prevalence and its associated factors among high school students across Iran. METHODS: Eligible participants were high school students from all grades studying in the fields of Theoretical branches. An online questionnaire comprised of two sections was distributed to the target population utilizing a convenience sampling method; the first section of the questionnaire focused on demographic data, while the second gathered ever and recent substance use history. Multivariable Poisson regression was used to identify independent factors associated with the number of different substances used by the participants. RESULTS: A total of 9402 individuals participated in this study, comprised of 56.9% males and 43.1% females. Of these, 3687 (39.2%) reported ever using at least one substance, and 2691 (28.6%) reported recent use. Among ever-users, 53.0% used more than one substance type; among recent users, 47.1% used more than one type. A greater number of substances used (ever or recent) was associated with older age, being married, attendance at nonpublic schools, lower grade point average, single-parent household, and lower parental education. CONCLUSION: A notable percentage of high school students had the experience of ever and recent substance use, underscoring the need for further preventive measures to address substance use among Iranian youth, with a focus on specific demographics.