Pattern of substance use among students of medical sciences in Tehran, Iran: A latent class analysis

Background: Entering university is an important developmental milestone that might be associated with behavioral change. The aim of this study was to identify the subgroups of university students on the basis of substance use, and to assess the role of demographic factors, ease of access to substances, and substance use among friends and family members on membership in specific subgroups. Methods: This cross-sectional study was performed in 2012-2013 using multistage random sampling among students of Tehran University of Medical Sciences (n = 1985). Anonymous, structured question-naires were distributed to the students in each selected class. Substance use was defined according to the cultural and epidemiological features. All of the analyses were performed using proc LCA in the SAS software. Results: Three latent classes were identified; namely, 1) non users, 2) users of low-stigma substances, and 3) drug users. Notably, 14.3% and 2.3% of the students were in the classes of "users of low-stigma substances" and "drug users", respectively. In this study, the prevalence of use of prescription-type opioids was higher than any other type of substances. Being male, having easy access to substance, cigarette or hookah smoking, and drug user among family and friends increase the odds of membership in the second and third classes compared to the first class. Conclusions: Although a small percentage of the students are in the drug users class, the prevalence of using particular drugs is quite high in this class. These results point out the critical importance of designing specific preventive interventional programs for university students.