Background The Psychiatric Assessment Schedule for Adults with Developmental Disabilities Checklist (PAS-ADD Checklist) is a screening instrument designed to help carers recognize likely mental health problems in people with intellectual disabilities (ID). To date there are no published PAS-ADD Checklist data on a large nonpsychiatric population of adults with ID, an important step towards developing norms for comparative purposes.

Methods Informants who had known participants for a median 24 months completed the PAS-ADD Checklist on 1155 adults with ID living in community, residential care and hospital settings in a county district in the North-east of England.

Results Normative data were obtained for the PAS-ADD Checklist for the study population with reference to gender, age, and type of residence. The overall prevalence of mental health problems was 20.1%, and the rates for affective/neurotic, organic and psychotic disorders were 14%, 3.9%, and 10.2%, respectively. Significant differences in the rates for particular disorders were found across gender, age and, residence type.

Conclusions The rates of mental disorders found in the study population were consistent with previous studies of general populations of people with ID using over-inclusive screening instruments. The PAS-ADD Checklist appears to be an easy-to-use and sensitive tool for identifying mental health cases in ID populations, but further investigation is required concerning the specificity of the instrument.