Validity of the schizophrenia diagnosis of the psychopathology instrument for mentally retarded adults (PIMRA): a comparison of schizophrenic patients with and without mental retardation.
The PIMRA schizophrenia scale is moderately reliable for adults with ID, but their symptoms look different from typical schizophrenia.
01Research in Context
What this study did
The team tested if the PIMRA schizophrenia scale works in adults with intellectual disability.
They compared two groups: adults with ID plus schizophrenia and adults with schizophrenia only.
Doctors used DSM-III-R rules to check if the scale matched real diagnoses.
What they found
The scale showed moderate reliability and agreed with DSM-III-R most of the time.
Adults with ID had more flat affect and disorganized speech than the non-ID group.
They also had fewer clear delusions, so clinicians need to look for different signs.
How this fits with other research
Ghaziuddin (1997) extends this work by showing that birth complications are common in ID adults who later develop schizophrenia. Taking an obstetric history can add useful context during assessment.
English et al. (1995) seems to disagree: they found no long-term adaptive behavior loss after schizophrenia in adults with Down syndrome. The difference is explained by the narrow Down-syndrome group versus the broader ID sample in the target paper.
de Bildt et al. (2003) used a similar validation approach with children, showing that two PDD screeners work better together. The same logic applies here: combine the PIMRA scale with clinical judgment for adults.
Why it matters
You now have a tested tool to spot schizophrenia in adults with ID. Expect less talk about voices and more about jumbled speech or blank faces. Pair the scale with a quick birth-history check as Ghaziuddin (1997) suggests. If the client has Down syndrome only, remember that adaptive skills may stay steady even after diagnosis. Document both positive and negative signs to keep treatment plans accurate.
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02At a glance
03Original abstract
The Psychopathology Instrument for Mentally Retarded Adults (PIMRA) was designed to assess psychiatric disorders among mildly and moderately mentally retarded persons. In a psychiatric population without mental retardation (n = 53), the PIMRA schizophrenia scale had an internal consistency coefficient alpha = 0.52. By removing one outlier item this increased to alpha = 0.61. By comparing the PIMRA schizophrenia diagnoses with DSM-III-R diagnoses in the psychiatric population, we found an external reliability corresponding to phi = 0.47 and an unweighted kappa = 0.43. Weighting of the mistakes resulted in a weighted kappa (w) = 0.74. A regression analysis of DSM-III-R diagnosis based on the PIMRA items was conducted. The regression equation was able to identify 75.5% of the DSM-III-R schizophrenic disorders in the psychiatric population. This equation correctly identified 75.5% of the PIMRA schizophrenias in a mentally retarded population. The intermethod reliability was phi = 0.49. We also compared the 38 psychiatric patients with DSM-III-R schizophrenic disorder with the 48 mentally retarded patients with PIMRA schizophrenic disorder. The mentally retarded patients had less delusions and more incoherence and flat affect. They also used less neuroleptic drugs.
Research in developmental disabilities, 1994 · doi:10.1016/0891-4222(94)90030-2