Background: Citizens’ mental health has been challenged by the advent of a new reality during the COVID-19 pandemic, which has imposed a new pattern of behavior on everyone. In this context, it is important to clarify how this new reality is impacting the mental health of Brazilian citizens. Design and setting: Cross-sectional study, Brazil. Methods: This work is part of the “IMPACT RESEARCH COVID19 BRAZIL: EVALUATING THE PANDEMIC BY COVID-19 THROUGH 24 QUESTIONS”. The implementation of the survey was carried out by distributing a questionnaire through social networks. Data collected was used to measure how much the experience of citizens in the pandemic period has impacted on their mental heath. All data analysis was performed using R. Results: Self-reported experience of negative symptoms and behaviors (sadness, loneliness, stress, anxiety, impatience), as well as exaggerated consumption of substances (alcohol, drugs) and use of electronic recreation (games), differs with age, with the youngest being the ones who most reported such experience, regardless of gender. However, no relevant statistical correlations were found between the variables mentioned above and others that could explain them, such as use of public transport, number of cohabitants, etc. Conclusions: other factors, related to distancing/social isolation, may be contributing to these negative manifestations.