Open Access Research article

Nonprescribed use of tranquilizers or sedatives by adolescents: a Brazilian national survey

Emerita S Opaleye1, Ana R Noto1*, Zila M Sanchez1, Tatiana C Amato1, Danilo P Locatelli1, Michael Gossop2 and Cleusa P Ferri1

Author Affiliations

1 Departamento de Psicobiologia, Universidade Federal de São Paulo, Rua Botucatu, 862- 1° andar, São Paulo CEP 04023-062, Brasil

2 King’s College London, Institute of Psychiatry, 4 Windsor Walk, London SE5 8AF, UK

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BMC Public Health 2013, 13:499  doi:10.1186/1471-2458-13-499

Published: 24 May 2013



Although the nonprescribed use of tranquilizers or sedatives by adolescents is a cause for concern in many countries, there is a shortage of data from low and middle income countries (LAMIC). The present study aims to estimate the prevalence of nonprescribed use of tranquilizers/sedatives by adolescents in Brazil, and to assess how socioeconomic and demographic circumstances, as well as indicators of access to these substances are associated with their use and with risk perception.


A cross-sectional study was conducted using a multi-stage probability sample of 18131 high school students from public and private schools from all 27 Brazilian state capitals. A self-reporting questionnaire was used to obtain information on social and economic circumstances, nonprescribed use of tranquilizers or sedatives and risk perception of their use.


Lifetime nonprescribed use of tranquilizers or sedatives was reported by 5% of respondents, more commonly among females (OR: 2.19, 95% CI: 1.75-2.75) and those attending private schools (OR: 1.47, 95% CI: 1.17-1.84). The use of tranquilizers/sedatives by relatives or friends was associated with nonprescribed use by the participant (OR: 4.26, 95% CI: 3.46-5.23) and a majority of lifetime users obtained these substances from a family environment (82%). Previous medical prescription was independently associated with nonprescribed use (OR: 6.61, 95% CI: 4.87-8.98) and with low risk perception (OR: 2.42, 95% CI: 1.12-5.24).


A substantial proportion of Brazilian adolescents use nonprescribed tranquilizers/sedatives. Easy access to these substances seems to play an important role in this use and should be tackled by preventive and treatment interventions.