Background: Classification of psychopathology using operationalized diagnostic criteria is one component of psychiatric assessment. Previous literature has demonstrated that there are limitations in the International Classification of Diseases-10 (ICD-10) and the Diagnostic and Statistical Manual-IV (DSM-IV) when used with adults with intellectual disabilities.
Methods: A literature search using Medline, PsychLIT and hand searching of key journals identified the existing literature, which was reviewed by the Diagnostic Criteria for Psychiatric Disorders for Use with Adults with Learning Disabilities/Mental Retardation (DC-LD) Development Working Group. Key findings are integrated into this paper. This, together with expert consensus led to the development of DC-LD, a new psychiatric classificatory system devised specifically for use with adults with intellectual disabilities. The new diagnostic criteria and classification within DC-LD were piloted with 52 field investigators drawing on 709 clinical cases. Validity of DC-LD classification was measured by comparison between the criteria providing DC-LD diagnosis and the gold standard of learning disabilities psychiatric assessment.
Results: In 96.3% of cases, the DC-LD diagnosis was fully concordant with that of clinical opinion. The few discrepancies related to level of detail.
Conclusion: DC-LD accommodates the pathoplastic effect of intellectual disabilities on psychopathology. Its use will hopefully improve clinical practice and facilitate research, but further work to determine its usefulness and limitations is required.