Rumination is a type of repetitive thinking, characterized by a focus on symptoms and their possible consequences. This pattern of thinking is related to several harmful consequences for the individual s life. Considering the relevance of these impairments, the aim of this dissertation was to investigate this construct in relation to other variables, and to evaluate the forms of treatment that are already being used to reduce ruminative thoughts. To this en aggressiveness in victims of child maltreatment. Article 1 describes this research, and the results point to the occurrence of child maltreatment as predictors of rumination and aggression in adulthood, while rumination also appears as a predictor of aggressiveness. These data show the negative impact of rumination, which indicates the need for interventions capable of reducing these thoughts. In this context, article 2 comprised a systematic review and a meta-analysis with randomized clinical trials that assessed psychological interventions to reduce rumination in a sample of children and adolescents. The results indicate, in general, the effectiveness of the interventions, but point out some limitations. Therefore, future studies should seek to improve treatment protocols focused on rumination.