Intellectual disability and the ICD-11: towards clinical utility?

Abstract

Purpose – The 11th revision of the International Classification of diseases which sets global standards for defining, reporting and managing health conditions is under way. The International Classification of Diseases (ICD) underpinning principle of clinical utility is currently poor for persons with Disorders of Intellectual Development (DID) and mental disorders. This impedes access to healthcare resources; services and social inclusion thereby further aggravating their vulnerability. The purpose of this paper is to present a critical overview and evidence informed recommendations within the context of an international collaborative programme, undertaken by the Faculty of Psychiatry of Intellectual Disability, Royal College of Psychiatrists, UK with support from the World Health Organisation (WHO). Design/methodology/approach – The authors carried out: first, a systematic review (SR) of literature, using PRISMA guidelines regarding the reliability, validity and utility of the ICD-10/Diagnostic and Statistical Manual of Mental Disorders (DSM) diagnostic criteria in people with DID (PWDID); second, a national and international consultation exercise with partners, stakeholders and experts; third, a multicentric survey of problem behaviours in PWDID; and finally, information dissemination/dialogues including presentations and workshops at key scientific events, consultation networking, data gathering and consensus building. Findings – The SR revealed a dearth of robust studies – most consisting of weak research methodologies. Significant difficulties were highlighted regarding the application of diagnostic criteria in the current classificatory systems – particularly in people with severe/moderate DID. Recommendations supported the introduction WHERE APPROPRIATE of modifications based on observed phenomena (signs) in PWDID in lieu of reported symptoms to facilitate DIAGNOSIS AND better access to healthcare and the community. Heterogeneity precluded quantitative pooling and meta-analysis. The consensus building exercise globally revealed that problem behaviours were the commonest reasons for referral to healthcare services with significant numbers without a diagnosed mental disorder being prescribed psychoactive medication. Research limitations/implications – The consensus gathering exercise WAS SELECTIVE AND did not cover all of the 194 member states of WHO due to resource and time constraints and this constitutes the main limitation of our study. Based on the SR and expert consensus, the authors submitted evidence informed pragmatic proposals to the WHO aimed at addressing the shortcomings of the ICD-10. The key recommendations focused on improving clinical utility within the context of epistemic iteration which would consolidate and strengthen the future evidence base. It was also recommended that self-injurious behaviour should form a standalone sub category in view of its relevance for healthcare services and resources which underpin clinical utility. Practical implications – The ICD-11 is a global, multidisciplinary and multilingual development for public health benefit with 70 per cent of the world's health expenditures assigned using this system for resource allocation. Currently mental disorders in PWDID can be misinterpreted, unrecognised and under reported resulting in barriers to access to treatment and healthcare resources. Conversely disorders may be over diagnosed when the inherent discrepancies between the chronological age and the developmental level of functioning are not considered. Conclusions and recommendations from this study will result in better diagnosis of mental disorders and healthcare resources in this population. Social implications – PWDID are a vulnerable sector of the population with an increased prevalence of mental health problems who are marginalised and discriminated by society. Early detection, treatment and management of these conditions will prevent further decompensation and stigmatisation. Originality/value – To the best of the authors knowledge this is the first comprehensive, large-scale study which evaluates the ICD classificatory system within the context of clinical utility for PWDID, including experts and stakeholders from both lower/middle- and high-income countries. The international consultation/consensus building process culminating in the formulation of evidence informed recommendations, aimed at improving the clinical utility of the ICD-11 for this population, has the potential to improve access to appropriate healthcare and treatment and consequent enhancement of their quality of life.