RÉSUMÉ
Background. There is lack of comprehensive data on substance use and associated factors among school students in Delhi, India. Methods. We used a cluster sampling method based on sections of classes in schools to conduct this study in two government-run schools in Delhi. All enrolled students from 8th, 9th and 11th grades participated (n = 405). The WHO Student Drug Use questionnaire was administered in a single session for a class section for assessing substance use. Results. The participation rate was 90.6%. The rates of past 12 months’ use of tobacco, alcohol, cannabis and inhalants were 22%, 12.1%, 12.1% and 8.6%, respectively, while rates for ‘sedatives and tranquillizers’ were 4.9%, opium 2.7% and other opioids 1.2%. Lifetime use of heroin was reported by two students and use in the past 12 months by one student. Multiple substance use was high. Higher age was associated with the use of alcohol and cannabis. According to logistic regression model results, use by a family member significantly increased the probability of using tobacco (adjusted odds ratio [AOR] 11.3; 95% confidence interval (CI) 3.4–37.8) and alcohol (AOR 3.75; 95% CI 5.1–1059.3). Similarly, use by peers significantly increased the probability of tobacco (AOR 7.7; 95% CI 2.0–29.8) and cannabis use (AOR 5.7; 95% CI 1.5–21.5). Having poor harm perception significantly increased the chances of inhalant use by students (AOR 5.5; 95% CI 1.5–20.1). Conclusion. The study results bring to attention the prevalent and important problem of substance use among schoolchildren. We recommend that (i) intervention strategies for school settings are important and need to factor in the use of illicit substances (cannabis); (ii) psychosocial intervention by trained school counsellors in school settings is the mainstay for intervention for cannabis and inhalants; and (iii) heroin users should be referred to healthcare facilities for detoxification.