FET framework was proposed to simplify classifications of psychiatric disorders (DSM, ICD) using 12 functional aspects of behaviour that this model highlights. Clinical studies showed good differential power of the FET framework for various diagnoses of psychopathology. For example, depressed people had low endurance and psychomotor slowdown in their temperament profiles. In contrast to them, patients with Generalized Anxiety Disorder had higher impulsivity and neuroticism. FET-developers suggested that every symptom in DSM/ICD diagnoses can be mapped into a specific FET code reflecting a disregulation within well-documented neurochemical systems.