The American Psychiatric Association is considering the inclusion of the psychosis risk syndrome as a new diagnosis for DSM-5. The main evidence supporting inclusion is: (1) the patients meet criteria for having a current illness, (2) the patients are at high risk for becoming more severely ill, (3) no DSM-IV diagnosis accurately captures their current symptoms or future risk, (4) the diagnosis is reliable and valid, at least in the research setting, and (5) codification in DSM-5 will promote treatment and prevention research of sufficient quantity and quality to permit the development of treatment guidelines. Field trials are needed to determine whether the proposed diagnostic criteria can be used with reliability in actual clinical practice.