The “defense mechanisms” are psychological processes, often followed by a behavioral reaction, implemented to deal with difficult situations, to manage conflicts, to preserve their functioning from the interference of disturbing, painful and unacceptable thoughts, feelings and experiences. They are generally, but not necessarily, automatic, as they often work without a conscious effort, as they are a preferential tool for dealing with a real or perceived danger. Dozens of authors and researchers have studied these psychological processes for about two centuries. The most representative, for systematicity, innovation and argumentative coherence, were undoubtedly the scholars closest to the psychodynamic schools.