Symptom rating scales for schizophrenia and other primary psychotic disorders in ICD-11

The subtype system for categorising presentations of schizophrenia will be removed from International Classification of Diseases 11th Revision. In its place will be a system for rating six domains of psychotic disorder pathology: positive symptoms, negative symptoms, depressive symptoms, manic symptoms, psychomotor symptoms and cognitive symptoms. This paper outlines the rationale and description of the proposed symptom rating scale, including current controversies. In particular, the scale could adopt either a 4-point severity rating or a 2-point presence/absence rating. The 4-point scale has the advantage of gathering more information, but potentially at the cost of reliability. The paper concludes by describing the field testing process for evaluating the proposed scale.