IntroductionThe dependence of psychotropic drugs is a great challenge for parents, health professionals, educators, public policy managers, legislators and for the whole community. The impact on society, the economy and the health of this disorder is immense. In the last decades, drug experimentation has been increasingly precocious, with abuse and dependency, despite the fact that preventive efforts are increasing [1, 2]. An individual's first experiences with drugs often take place during adolescence. During this phase, the individual is particularly vulnerable from a psychological and social point of view [3]. Thus, it is particularly important to study this age group in detail, especially in relation to frequent and heavy use of legal and illegal drugs and to identify the psychological and sociocultural factors that are associated with such use [4,5].In Brazil, six major epidemiological studies on the use of licit and illicit drugs were carried out in the last two decades. Alcohol is the most commonly used psychotropic drug. However, the use of marijuana has increased considerably among Brazilian students [4,6,7]. Several national and international studies have analyzed the associations of psychological and socio-cultural factors with AbstractBackground: Globally, the use of illicit drugs is a public health problem. Generally, the use of licit drugs tends to precede and increase the risk of regular use of illicit drugs. Since, the family environment can influence this process. In Brazil, marijuana is the most commonly used illicit drug, especially among adolescent users. In northern Brazil, epidemiological studies of illicit drug use in the population of adolescents and young people are still scarce. This study determined the prevalence and factors associated with the regular use of marijuana and cocaine among high school students in the municipality of Breves, Pará, Brazilian Amazon. Methods:This cross-sectional study was carried out in four high schools in the municipality of Breves, in which a self-filling form was used to collect information and enable the description and analysis of socio-demographic, economic and family conditions related to the regular use of illicit drugs. Chi-Square and Odds Ratio tests were used to indicate and quantify the contribution of factors associated with regular use of illicit drugs.Results: Among 3,218 students, 1,828 (56.8%) agreed to participate in this study. The age range was 14-52 years, with predominance of female students (55.6%). The prevalence of experimentation and regular use of marijuana and cocaine was 8.8% and 4.0%, respectively. The average initial age of use of marijuana and cocaine was 13.5 years. Most students who regularly use illicit drugs use only marijuana (81.1%). Several factors associated with regular use of illicit drugs have been identified. In particular related to social, economic and demographic aspects. Conclusion:The prevalence of students using illicit drugs is moderate in the municipality of Breves. Possibly, regular use of marijuana and ...