The lack of information and stigma associated with mental disorders are major obstacles to the promotion of mental health. The "UPA Makes the Difference: Mental health awareness intervention in schools" project aims to contribute to increase young people knowledge regarding mental health issues. This project is part of the "United to Help Movement", focusing on the combat of mental illness stigma and discrimination. Objectives: to describe the psychometric characteristics of the questionnaire UH (United to Help) and to verify the adequacy of action to promote mental health. Methods: this study was conducted with 26 students (15-17 year-olds). The mental health intervention is composed by 2 sessions. The questionnaire was administered at the beginning of the 1st session and in the end of the 2nd session. Results: cronbach'salpha regarding 2 sections of the "Questionnaire UPA" stated poor and acceptable levels of internal consistency (stigmatizing perceptions and perceptions of knowledge, respectively). The post intervention assessment showed a significant increase in the total score of the perceptions of knowledge; no significant differences in stigmatizing perceptions; and a significant decrease in help-seeking intentions when facing a mental health problem, although most participants have come to consider different types of help. Conclusion: the results suggest the need to review the structure of the "stigmatizing perceptions" section of the questionnaire, as well as to conduct new analyses with a larger sample. Furthermore, results show the adequacy of the methodology used in the intervention, particularly in the capacity showed to promote the increase of knowledge regarding mental health issues.