Tuesday, 17 May 2022

General Note

General Note

Caveats in rating the PANSS are commented on since it has been the standard scale amongst others. Double-blind studies have offered the most solid evidence, whereby independent raters assess the patients at baseline and typically the same raters follow the same patients throughout. If one wishes to maintain true blindness, every assessment can be performed by the different rater, which obviously poses two major problems—feasibility (to assure adequate number of raters) and reliability among raters.


Therefore, two possibilities in a typical study should be noted as confounding factors in quantification with the scales. First, the result of the baseline assessment will have a significant impact for later assessments. As for a rater effect at the very baseline, it is reported that a psychiatrist who saw a patient for the first time underrated the PANSS scores by 10%, compared with the ones obtained by the psychiatrist in charge who has known that patient very well.56 Second, if a better psychological interaction between patients and assessors happens with more encounters, patients may feel less guarded to express themselves more frankly (for instance for their hidden delusions).


Contrarily, another possibility is assessors get psychologically accustomed to patients, which might not necessarily result in more severity in scoring (in lieu of a possible increase in identifiable symptoms). These issues are expected to affect rater drift within the rater across longitudinal assessments. Use of performance-based, objective rating scales could overcome these issues but they are mostly applicable to cognitive measurements in general and a part of functional scales. As such, although rater effect and rater drift issues have rarely been the target of studies, more work is clearly indicated for the purpose of better ‘quantification’ with the rating scales.


Finally, given various needs in patients with schizophrenia, it might be appropriate to make use of the scales that are miscellaneous in nature. Examples are the targeted inventory on problems in schizophrenia: TIP-Sz30 (10 items) and the Investigator’s assessment questionnaire: IAQ57 (10 items). On the other hand, apart from more time requirement and a possibility that patients may not tolerate lengthy assessments, use of multiple scales renders summarizing the data more challenging. In this context, separate reporting of the parent study is common, although tracing the studies is sometimes complicating.


The author recommends that global functioning should always be reported with a simple scale since it could represent the most proximal effects of various distal elements in the illness. More work is necessary on ‘subjectivity’ regarding the subjective assessment scales in patients with schizophrenia. Further, it would be useful to have the scale that is comprehensive for both motor plus non-motor adverse effects.

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