When the error corrects the model: vomiting

This work shows the phases that have lead to the individuation of a new eating disorder: the Vomiting. After a first introduction on eating disorders, according to the DSM-IV, the action research phases are presented – problem and goals definition, hypotheses definition, hypotheses application for changing, and effects evaluation –. Brief strategic therapy is illustrated as an Action Research, based on process circularity and flexibility, where the problem is known through its solution.