The COVID-19 pandemic and its containment measures have brought several impacts to the physical and mental health of the world s population. Adolescence is a development s stage of psychological vulnerability and tends to be highly impacted by a stressor of this magnitude. Thus, in this dissertation, symptoms of anxiety and depression in adolescents during the health crisis were researched through two separate articles. The first one is a systematic review of cohort studies produced between 2020 and 2021 that evaluated depression and/or anxiety s symptoms in adolescents, as well as associated risk and protective factors. The second article is a cohort research carried out with adolescents between twelve and seventeen years old, residents of the Rio de Janeiro city, over an year, in which sociodemographic characteristics, lived experiences and symptoms of anxiety and depression were studied. The results indicate high prevalence of anxiety and depression in adolescents from Rio de Janeiro and in most of the countries analyzed. Sociodemographic risk and protection factors were similar in Brazil and worldwide. As a differential, in the second research, it was possible to evaluate not only the adolescents personal variables, but also Rio de Janeiro s epidemiological data from the pandemic itself, which also proved to be predictive variables on mental health outcomes. These data can be used to help understand the impacts of the pandemic context, as well as guide prevention and intervention measures in the population studied. Finally, developments in additional research are proposed for a precise understanding of the current scenario.