Reliability and Clinical Utility of ICD-11 Diagnostic Guidelines for Severe Mental Disorders in Nigeria

Background: An essential foundation for global mental health is the development of reliable, clinically useful and globally applicable diagnostic classification of mental disorders. Aim: This study is aimed at assessing the inter-rater reliability and clinical utility of the proposed diagnostic guidelines for severe mental disorders in the eleventh edition of the International Classification of Diseases and Related Health Problems (ICD-11) in Nigeria. Method: The study was conducted in Nigeria at 2 mental health facilities as part of a 13 country project coordinated by the World Health Organization. Following training, 32 clinician raters assessed the reliability and clinical utility of the proposed diagnostic guidelines for schizophrenia and other primary psychotic disorders, mood disorders, anxiety and fear-related disorders, and disorders specifically associated with stress. Using SPSS version 21, analysis of data was conducted at the Data Coordinating Center (DCC), Columbia University. Results: For reliability, estimates of intraclass κ coefficients for diagnoses ranged between 0.71 (Schizoaffective disorder) and 0.93 (Schizophrenia). In ratings of the clinical utility, the guidelines were perceived as easy to use, corresponding accurately to patients’ presentations (i.e. having satisfactory goodness-of-fit), clearly understandable, and as providing useful guidance on distinguishing a disorder from normality and from other mental disorders. Conclusion: Overall, the reliability of the diagnostic guidelines was good in Nigeria, ranging from substantial to almost perfect. Utility ratings were generally satisfactory. The results support the suitability of the ICD-11 diagnostic guidelines for implementation at a worldwide level.