The reliability and clinical utility of ICD-11 schizoaffective disorder: A field trial.

A major goal for the revision of the International Classification of Diseases and Related Health Problems, Tenth Edition (ICD-10) is to increase the clinical utility of the diagnostic system. Schizoaffective disorder has a history of poor diagnostic reliability due to the similarities and overlap in symptoms that it shares with other disorders, especially primary psychotic and mood disorders. The present study was part of the case-controlled field trials for ICD-11 and examines how the proposed changes for schizoaffective disorder may improve differential diagnosis and diagnostic accuracy. Clinicians from around the globe (n = 873) were provided with either ICD-10 or ICD-11 diagnostic guidelines and asked to apply them to case vignettes comparing schizoaffective disorder to schizophrenia and mood disorders with psychotic symptoms. Participants were asked to respond to follow-up diagnostic questions to determine which components of the diagnostic guidelines affected diagnostic accuracy. Overall, clinicians showed small improvements in accurately diagnosing vignettes using ICD-11 over ICD-10. Results suggest the discrepancy in diagnosing schizoaffective disorder is related primarily to the presence of mood symptoms and discrepancies about whether those symptoms are more consistent with schizoaffective disorder or a mood disorder diagnosis. Continuing to identify ways to more accurately capture this symptom picture will be important in the future as well as systematic efforts to educate clinicians about differential diagnosis.

Psychotic disorder symptom rating scales: Are dichotomous or multi-point scales more clinically useful?-An ICD-11 field study.

Classifications of psychotic disorders are moving towards utilizing dimensional symptom domains as the preferred mechanism for describing psychotic symptomatology. The ICD-11 has proposed six symptom domains (Positive symptoms, Negative symptoms, Depressive symptoms, Manic symptoms, Psychomotor symptoms, and Cognitive symptoms) that would be rated in addition to providing a psychotic disorder diagnosis. This study investigated clinicians' use of dichotomous versus multi-point scales for rating these six domains. Global mental health professionals (n = 273) rated case vignettes using both a 2-point and 4-point version of a rating scale for the six domains. Clinicians were more accurate using the 2-point scale in absolute terms, but after correcting for chance guessing and disagreements, the two versions of the scale were equally accurate. Clinicians believed the 2-point scale would be easier to use, although they also indicated that the 4-point scale would provide richer clinical information. Participants were able to detect the presence of psychotic symptom domains in the vignettes with good reliability with no special training using either scale. We recommend that clinicians and researchers use the version of the scale that best matches their purpose (i.e., to maximize accuracy or enhance case description). Future work should develop the implementation characteristics of the scale to improve its potential for global application.