A rasch model to test the cross-cultural validity in the positive and negative syndrome scale (PANSS) across six geo-cultural groups

BACKGROUND: The objective of this study was to examine the cross-cultural differences of the PANSS across six geo-cultural regions. The specific aims are (1) to examine measurement properties of the PANSS; and (2) to examine how each of the 30 items function across geo-cultural regions. METHODS: Data was obtained for 1,169 raters from 6 different regions: Eastern Asia (n = 202), India (n = 185), Northern Europe (n = 126), Russia & Ukraine (n = 197), Southern Europe (n = 162), United States (n = 297). A principle components analysis assessed unidimensionality of the subscales. Rasch rating scale analysis examined cross-cultural differences among each item of the PANSS. RESULTS: Lower item values reflects items in which raters often showed less variation in the scores; higher item values reflects items with more variation in the scores. Positive Subscale: Most regions found item P5 (Excitement) to be the most difficult item to score. Items varied in severity from −0.93 [item P6. Suspiciousness/persecution (USA) to 0.69 item P4. Excitement (Eastern Asia)]. Item P3 (Hallucinatory Behavior) was the easiest item to score for all geographical regions. Negative Subscale: The most difficult item to score for all regions is N7 (Stereotyped Thinking) with India showing the most difficulty Δ = 0.69, and Northern Europe and the United States showing the least difficulty Δ = 0.21, each. The second most difficult item for raters to score was N1 (Blunted Affect) for most countries including Southern Europe (Δ = 0.30), Eastern Asia (Δ = 0.28), Russia & Ukraine (Δ = 0.22) and India (Δ = 0.10). General Psychopathology: The most difficult item for raters to score for all regions is G4 (Tension) with difficulty levels ranging from Δ = 1.38 (India) to Δ = 0.72. CONCLUSIONS: There were significant differences in response to a number of items on the PANSS, possibly caused by a lack of equivalence between the original and translated versions, cultural differences among interpretation of items or scoring parameters. Knowing which items are problematic for various cultures can help guide PANSS training and make training specialized for specific geographical regions.