Sobre álcool, cigarros e outras drogas : uma análise sobre escalonamento e complementariedade do uso de drogas lícitas e ilícitas por escolares brasileiros

Abstract

This dissertation objectivates to analyze the connection between the use of alcohol and cigarettes and their influence on the use of illicit drugs for the students participating in Pesquisa Nacional de Saúde do Escolar 2015 (PeNSE 2015). Thus, two essays are presented concerned with investigating different features of that association. The first essay is concerned with identifying the characteristics associated with initiation and sequencing of the drugs studied. Two methodologies are employed to accomplish that. The first was the estimation of a multivariate probit model to identify the characteristics which increase or decrease the likelihood of initiation into alcohol, cigarettes, and illicit drugs usage. The second methodology consists on the estimation of a survival regression system to analyze the characteristics associated with the acceleration and deceleration of the age which PeNSE 2015 students make the first consumption of these goods. The survival analysis presented was also modified to accommodate a sample selection process associated with initiation to each of the drugs studied. Results indicate that the consumption of alcohol and cigarettes increases the likelihood of initiating the use of illicit drugs. Results also suggests that the postponement of initiations to alcohol and cigarettes also delay the first consumption of illicit drugs. It was also observed that the initiation of both alcohol and cigarettes are associated with the acceleration of lifetime until the initiation of the use of illicit drugs. The second essay presented in this dissertation aims to identify the presence of complementarity, substitution, or independence between the consumption of alcohol and cigarettes towards the consumption of illicit drugs. The consumption of these goods is identified accordingly the frequency period of thirty days prior to the application of the survey in which PeNSE 2015 students declared to consume those. The second essay presented employs an instrumental variable approach on an ordered response model which also accounts for sample selection to isolate the endogeneity of the frequency of consumption of alcohol and cigarettes. The results presented suggest that alcohol and illicit drugs present a complementary pattern where alcohol consumption is less frequent and independence when this consumption is more frequent. The results presented also indicate that cigarettes and illicit drugs are substitute goods across all levels of cigarettes consumption, being that effect increasing as cigarettes day to day consumption becomes more frequent.