This study seeks to analyze the experiences of populations which suffered forced displacement due to the construction of the Itá Hydroelectric Power Plant in southern Brazil by observing the interfaces between this process and mental health. This is a qualitative study based on participant research. The data were collected from February to December 2016, with the participation of 43 people, and subjected to content analysis. The results indicate that the distress factors included situations of violence and the violation of the rights of those who were affected, high impacts on people’s lifestyles and mental health, and environmental changes. We conclude that there is a need to discuss the impacts of the construction of dams and its interactions with the mental health of those who are affected.