Background:
Tobacco, alcohol and cannabis are among psychoactive substances with the highest prevalence of use in many countries. In addition, there is vast evidence in the literature on the clustering of these substances use among adolescents.

Objective:
Our aim was to determine different groups of adolescents according to their use of tobacco, alcohol and cannabis as well as factors associated with co-occurrence of these substances use.

Methods:
To explore patterns of tobacco, alcohol and cannabis use among Serbian students aged 15–16 years, we used data obtained through Pilot survey Health behavior in school-aged children, conducted in 2017 on a nationally representative sample. Latent class analysis (LCA) was conducted and classes were compared according to sociodemographic characteristics.

Results:
In 2017, in Serbia, among students aged 15–16 years (n=1408), 23.5% reported smoking, 51.3% drinking alcohol and 6.7% using cannabis in the last 30 days. Based on the last month’s tobacco, alcohol and cannabis use, using LCA (AIC=4771.771; BIC=4855.644; entropy=0.9), students were grouped into: those who do not use any of the explored substances (abstainers); predominantly smokers; users of alcohol and cigarettes; and users of all three substances. More students are in the group of alcohol and tobacco users compared to the predominant smokers’ group (4.0% vs 37.9%). Compared to abstainers, students in the predominant smokers’ group have twice higher odds of reporting health complaints at least twice a month (OR=2.10; 95% CI: 1.11–3.99).

Conclusions:
To address dual and poly substance use there is a need to carefully plan the interventions which should address multiple risk factors and strengthen protective factors.