This research paper will introduce the first results of a Franco-Brasilian study which compares the psychic functioning of adolescents who assault "sexually" and of adolescents who self-harm. These teenagers were met in various environments and assessed with the help of projective tests (Rorschach, TAT). We will focus on how the instinctual sexual impulses (representations/affects) is processed and on the identification issue. Common to the two groups are the narcissistic fragility components. The difference lies within aggressive impulses: in the case of the self-harm group, the turning upon the self would imply a difficulty to attack the other, hence the other being attacked from within the self. In the case of the other group who abuse sexually, the harm is directed towards some parts of the self, whereas "sexual" hetero-assault would indicate a state of confusion where parts of the self and parts of others are not differenciated, where it is the disowned part of the self (believed to belong to the other) that is being assaulted. With the former, the masochistic element of affect and depressive state better acknowledged, whereas the behaviour of the latter suggests a narcissistic triumph that supports the denial of the depressive state.