The WHO ICD-11 classification and diagnosis of mental disorder in people with disorders of intellectual development (PWDID): An international study on clinical utility

Abstract

Introduction

Constituting 2% of the population, PWDID are a vulnerable group with a higher prevalence of mental disorders than the general population. ICD diagnostic criteria often rely on adequate cognitive functioning and hence diagnosis of mental disorders in PWDID can be difficult, consequently leading to inequity of treatment, prognosis and stigma. Our study critically analysed the available evidence base and explored the feasibility of applying modified diagnostic criteria within the context of cumulative iterative iteration. We present the outcome using diagnosis of DID and anxiety disorder as examples.

Aims

Address current shortcomings in ICD classification regarding PWDID by contributing effectively to the WHO ICD-11 consultation process in collaboration with international stakeholders.

Objectives

Facilitate accessibility of ICD-11 criteria for diagnosis of mental disorders capable of engendering robust evidence based epidemiological data and healthcare in PWDID.

Methods

We evaluated current evidence via a systematic literature search utilising PRISMA guidelines and developed pragmatic guidelines to adapt ICD diagnostic criteria in PWDID. A brief screener [Glasgow Level of Ability and Development Scale (GLADs)] for detecting DID was also studied internationally within the context of clinical utility (n = 136).

Results

The evidence base relating to mental disorders in PWDID is poor, significantly hampered by difficulties in applicability of diagnostic criteria. The GLADs appears to be a promising screening tool with good clinical utility for detecting disorders of intellectual development (DID) particularly where resources are scarce.

Conclusions

Pragmatic modifications to ICD-11 diagnostic criteria and the GLADS tool facilitates its clinical utility for PWDID and contributes significantly to enhancing research based evidence, and, ultimately their health access and well-being.

Disclosure of interest

The authors have not supplied their declaration of competing interest.