Polydrug Use and Co-occurring Substance Use Disorders in a Respondent Driven Sampling of Cocaine Base Paste Users in Santiago, Chile

Carla F. Olivari, Jorge Gaete, Nicolás Rodriguez, Esteban Pizarro, Paloma Del Villar, Esteban Calvo, Alvaro Castillo-Carniglia*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


We characterized substance use patterns and co-occurring substance use disorders among active cocaine base paste (CBP) users in Santiago, Chile using data from respondent-driven sampling (RDS) in three areas of Metropolitan Santiago. Recruitment began with nine seeds, reaching 398 active CBP users (18% women; mean age 37.7 years), defined as persons consuming CBP at least twice per week in the last three months. Population proportions and uncertainty were estimated accounting for individuals' social network and homophily. The median CBP age of initiation was 21 years, and the median number of years using CBP was 7 for women and 15 for men. The median days of use in the past month was 25 days, with a median of 56 doses per week. The proportion of monthly income spent on CBP was 65%. The prevalence of substance use disorders (SUDs) were: 98% for CBP, 67% for alcohol, 60% for marijuana, and 41% for cocaine hydrochloride. Heavy polydrug use patterns and co-occurring SUDs are frequent among active CBP users in the metropolitan area of Santiago. Traditional surveillance strategies may have underestimated polysubstance use and co-occurring SUDs in active CBP users. RDS proved to be a feasible methodology that could be effectively used for substance use surveillance among hard-to-reach populations.

Original languageEnglish
Pages (from-to)348-357
Number of pages10
JournalJournal of Psychoactive Drugs
Issue number4
Early online date2 Nov 2021
StatePublished - 2021

Bibliographical note

Funding Information:
This study was funded by the Chilean National Service for Prevention and Rehabilitation of Drug and Alcohol Consumption (SENDA), Contract Nº662237-38-LE13 to the Institute of Sociology, Pontificia Universidad de Católica de Chile. SENDA had no role in the study design, collection, analysis or interpretation of the data, writing the manuscript, or the decision to submit the paper for publication. Dr. Alvaro Castillo-Carniglia received research funding from FONDECYT Regular #1191282, Dr. Esteban Calvo from FONDECYT Regular #1181009, and Dr. Jorge Gaete received funding from grant FONDECYT Regular #1181724 and the Millennium Science Initiative of the Ministry of Economy, Development and Tourism, grant “Millennium Nucleus to Improve the Mental Health of Adolescents and Youths, Imhay.” We would like to thank Andrés González-Santa Cruz for his assistance in preparing Figure 1.

Publisher Copyright:
© 2021 Taylor & Francis Group, LLC.


  • Chile
  • Smoked cocaine
  • respondent-driven sampling
  • substance use disorder
  • surveillance


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