A psychometric evaluation of a Swedish version of the psychopathology inventory for mentally retarded adults (PIMRA)

Abstract

Given the difficulties with symptom identification and the assessment of mental health problems in persons with intellectual disabilities (ID) there has been a focus on the development of relevant assessment schedules for persons with ID. A Swedish version of the psychopathology inventory for mentally retarded adults (PIMRA, informant version), an instrument designed for identification of specific mental health problems in persons with ID, was evaluated in terms of inter-rater reliability, internal consistency, item grouping, criterion and concurrent validity based on a sample of 101 adults with different levels of ID. The Swedish version of the PIMRA had low inter-rater agreement on specific items but good agreement on low or high total score. In order to investigate internal validity, principal component analyses (PCA) were conducted in steps. Consequently, the majority of the 26 items, which remained after three PCA analyses, were grouped in a pattern approximating five of the original PIMRA subscales. The present analysis identified no item grouping matching the original Affective disorder subscale. Based on these results a revised Swedish version was developed. The concurrent validity analysis yielded a strong association between the total scores of the PIMRA and Reiss Screen for Maladaptive Behaviour (RSMB), between subscales on both instruments describing psychotic symptoms and between the RSMB subscale Aggressive behaviour and the PIMRA subscale Adjustment problems. The outcome of the criterion validity analysis indicated that individuals with a clinical diagnosis obtained higher total PIMRA scores than individuals without a clinical diagnosis and a comparison between the PIMRA subscale Psychosis and the clinical diagnosis indicating psychoses according to DSM-III-R or DSM-IV yielded a higher specificity than sensitivity measure. The results indicate that the PIMRA had a potential to identify individuals with mental health problems in persons with different levels (mild, moderate and severe) of ID and identify individuals with a specific mental disorder. Thus, professionals might use the PIMRA as a complement in the diagnostic process.