Using Treatment Response to Subtype Schizophrenia: Proposal for a New Paradigm in Classification

Phenomenology and Diagnosis The treatment and classification of schizophrenia continue to represent an enormous challenge. Phenomenology and outcome remain the basis of present classification systems although both are heterogeneous and overlap with other psychiatric disorders.1,2 Efforts are in place for change; eg, the Working Group on Classification of Psychotic Disorders for ICD-11 has recommended omitting the traditional subtypes such as paranoid, catatonic, etc., in accordance with DSM-5, the major argument being lack of clinical utility in routine clinical practice.3,4 We believe the changes advocated do not go far enough because classification still relies heavily on symptom clusters. Adding severity and course specifiers, as is the case in the ICD-11 draft, or multiple dimensions (DSM-V) may represent more of a challenge than benefit for clinicians in their busy daily practices. Moreover, the reliability and predictive validity of these specifiers and domains are not well established and, possibly, not substantively better than the subtypes that have been abandoned.