Early detection and treatment of illness are fundamental in providing optimal health care. However, this is a major challenge in mental illness, where diagnoses depend on symptom manifestation and the symptoms are often on a continuum with behaviors observed in the non-ill population. During the past 25 years, substantial progress has been made in identifying clinical high risk for psychoses with extensive validation and the beginning of treatment trials for symptom reduction and secondary prevention of psychoses. Attenuated psychosis syndrome is placed in Section 3 of the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, as a new disorder for further study. But the value and wisdom of creating a new disorder are hotly debated. The author advocates establishing a new disorder class as essential for progress. Key reasons to justify this view are described. Reasons to oppose the creation of a new class are briefly described.