Instrumental assessment of psychotic disorders in intellectual developmental disorders and autism with cognitive or...

The high comorbidity and complex clinical presentation of psychotic disorders in adults with intellectual developmental disorders (IDDs) and autism spectrum disorder with cognitive or major communication issues (ASD-CMCI) requires highly accurate assessment approaches. This targeted review examines the availability, validity, and clinical utility of existing instruments for this high-risk population, in whom diagnostic procedures are often hindered by communication deficits and diagnostic overshadowing.

There is a substantial lack of PD-specific assessment tools for this population. Adapted neurotypical scales, including the PANSS and PSYRATS, demonstrate limited validity because they rely heavily on introspective self-report. The primary methodological challenge is distinguishing chronic neurodevelopmental features from acute psychotic change, a process that requires careful observation of objective deviations from the individual's baseline functioning and behaviour.

This targeted review underscores the need for dedicated, informant-based instruments for PD in IDD/ASD-CMCI. Approaches grounded in behavioural equivalents and systematic evaluation of change from baseline appear essential for reducing diagnostic overshadowing and improving diagnostic accuracy, although further validation of these methods remains necessary.