Psychometric properties of the Neuropsychiatric Inventory for adults with intellectual disability

Abstract

BACKGROUND: Problem behaviours are common among people with intellectual disabilities (ID), but psychometrically evaluated instruments for assessing such behaviours are scarce. The present study evaluated the psychometric properties of the Neuropsychiatric Inventory-Intellectual Disability (NPI-ID). METHOD: We assessed 108 residents with intellectual disabilities living in group-homes using the NPI-ID, which included the 12 symptoms of the original NPI-Nursing Home and two supplementary symptoms: self-injurious behaviour and impulsive risk-taking behaviour. RESULTS: The NPI-ID showed adequate internal consistency (α = 0.76) and test-retest reliability (intraclass correlation coefficient = 0.88). Exploratory factor analysis revealed five factors accounting for 64.1% of the variance. Cluster analysis revealed that residents were clustered in three groups with distinctly different symptom profiles. CONCLUSIONS: The psychometric properties were satisfactory, supporting the use of the NPI-ID as a screening tool for people with intellectual disabilities. Additional research is needed to further evaluate the utility of the NPI-ID among people with intellectual disabilities.