Psychiatric Symptoms Associated with Dementia in Older People with Learning Disability

BACKGROUND: This paper describes a study of non-cognitive features of dementia in a population of 105 people over 50 years of age, with learning disability. METHOD: The study involved psychiatric assessment using the Psychiatric Assessment Schedule for Adults with a Developmental Disability (PAS-ADD), a semi-structured psychiatric interview developed specifically for people who have learning disability. Dementia was diagnosed using a combination of informant interviewing and observation of cognitive change over a three year period. RESULTS: Sample members with definite dementia had higher levels of sleep difficulty, hypersomnia, irritability, inefficient thought, loss of interest and anhedonia. Discriminant function analysis showed that non-cognitive features could help discriminate between definite and probable cases. CONCLUSIONS: Results support the previously reported observation for the general population that cognitive and non-cognitive features are only weakly related. The study suggests that psychiatric symptom information may be useful in screening for dementia in people with learning disability.