This article analyzes the mental stage though the paradigm of the theatrical stage, from the original angle of the actor’s creating process. How does embodying a character in acting mobilize the actor in a new relation to the self and to the other? Analyzing the mental process of embodying a character leads us to consider complex subjective problematics. Next, we apply this hypothesis to the clinical practice of theatrical mediation with adolescents in mental suffering by looking at a case. This will allow us to further examine this paradoxical dynamic in which acting an other leads one to feel oneself to be a subject.