Introduction Schizophrenia and other psychotic disorders are debilitating diseases with a devastating impact on patients’ lives. During the several lasts decades an emphasis on the prodromal stage of the psychotic disorders was noted. It was established that early interventions during this phase will prevent the development of full blown psychosis. Several interviewing measures were obtained, by constructing the most common presenting signs and symptoms of these pre-psychotic phases in order to identify Ultra high risk (UHR) patients, i.e. patients in a high risk of developing a first psychotic episode. This identification led to the construction of criteria aimed to specifically define these patients as in risk of developing psychosis: Psychosis risk syndrome (PRS) criteria.