Abstract
INTRODUCTION: Adolescence is a critical period of human development, where adaptive or maladaptive experiences can happen. These experiences are associated with psychological, social, biological and health factors. Previous empirical evidence suggests that mental health is associated with individual assets and positive states, whose presence may become a factor of protection and resistance to mental disorders. Among these, optimism could play a fundamental role in sustaining physical and mental well-being and in dealing with threats potentially harmful to health. Given the rise of research on optimism and its importance in the various health outcomes, it is necessary to initiate processes of compilation and synthesis of this evidence to facilitate the understanding of the importance of this variable on the mental health of adolescents. METHODS AND ANALYSIS: The included studies will be experimental, observational, cross-sectional and longitudinal focussed on the role of optimism on mental health in adolescents, regardless of whether they belong to clinical or non-clinical populations. This systematic review protocol will be carried out following the Cochrane Manual for systematic reviews and will follow the statement on systematic reviews and meta-analysis of PRISMA-P (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols). Searches will run from October 2019 to March 2020, and will be carried out from the following electronic databases: APA PsycNet, BVS (Biblioteca Virtual em Saúde), Web of Science, PubMed Central and Scopus. Two reviewers will obtain the eligible articles, published from January 2009 onward, to assess the quality of each study and extract the data. For the presentation of the results, a narrative and quantitative synthesis will be carried out that groups the data found. ETHICS AND DISSEMINATION: The approval of an ethics committee is not required for a systematic review protocol. The results will be presented at congresses in social sciences and psychology and will be published in a peer-reviewed social or health science journal. PROSPERO REGISTRATION NUMBER: PROSPERO CRD42019142616.