Clinical validation of ratings on the six-item Positive and Negative Syndrome Scale obtained via the Simplified Negative and Positive Symptoms Interview.

BACKGROUND: The six-item version of the Positive and Negative Syndrome Scale (PANSS-6) has shown promise as a brief measure of the severity of core symptoms of schizophrenia. However, since all prior analyses of the PANSS-6 were based on data extracted from studies using the full 30-item PANSS (PANSS-30), it remains unknown whether it is possible to obtain valid information for the PANSS-6 ratings via a brief interview, such as the Simplified Negative and Positive Symptoms Interview (SNAPSI). AIMS: We aimed to validate the PANSS-6 ratings obtained via the SNAPSI using the PANSS-6 scores extracted from the PANSS-30 ratings obtained via the comprehensive Structured Clinical Interview for PANSS (SCI-PANSS) as the gold-standard reference. METHODS: The PANSS-6 ratings based on the SNAPSI and the PANSS-30 ratings based on the SCI-PANSS were conducted by independent raters with established inter-rater reliability. RESULTS: Seventy-seven inpatients with schizophrenia (Mage = 35.1 ± 11.7 years; males = 57%; paranoid schizophrenia = 75%) participated in the study. The intraclass correlation coefficient (ICC) of the PANSS-6 total scores obtained using the SNAPSI and the PANSS-30-derived PANSS-6 total scores via the SCI-PANSS was 0.77 (p < 0.001). The ICC for the PANSS-6 total score and the PANSS-30-derived PANSS-8 (Andreasen's remission criteria) was 0.75 (p < 0.001). Spearman's rank correlation coefficient for changes in PANSS-6 total scores via the SNAPSI and changes in PANSS-30-derived PANSS-6 total scores was 0.70 (p < 0.001). CONCLUSIONS: Using the SNAPSI to rate the PANSS-6 enables a focused and brief assessment of the severity of core symptoms of schizophrenia, which facilitates measurement-based care and clinical decision making in the treatment of schizophrenia.

Inter-rater reliability of ratings on the six-item Positive and Negative Syndrome Scale (PANSS-6) obtained using the Simplified Negative and Positive Symptoms Interview (SNAPSI).

PURPOSE: The six-item version of the Positive And Negative Syndrome Scale (PANSS-6) is a brief rating scale focusing on core symptoms of schizophrenia. In order to facilitate rating of PANSS-6 and selected items from other common psychiatric rating scales, we recently developed the Simplified Negative and Positive Symptoms Interview (SNAPSI). The objective of the present study was to test the inter-rater reliability of PANSS-6 ratings obtained using the SNAPSI. MATERIALS AND METHODS: Using the SNAPSI, seven raters (psychiatrists, first-year psychiatry residents and psychologists) performed a total of 56 PANSS-6 ratings of 12 in- or outpatients with schizophrenia. As a measure of inter-rater reliability, we calculated the intra-class correlation coefficient (ICC, ≥0.75 = excellent, 0.40-0.74 = fair to good, <0.40 = poor) for the PANSS-6 total score and individual item scores. Furthermore, for the PANSS-6 total scores obtained by the six noncertified PANSS raters, we calculated the median deviation from the PANSS-6 total scores obtained by the only certified PANSS rater. RESULTS: The ICC for the PANSS-6 total score was 0.74 (F = 2.84, p = .03). The ICCs for the six individual PANSS-6 items ranged from 0.45 (N6 - Lack of spontaneity & flow of conversation) to 0.76 (P3 - Hallucinatory behavior). The PANSS-6 total scores obtained by the six noncertified PANSS raters deviated by a median of 12.7% (interquartile range: 6.2-20.0) from the PANSS-6 total scores obtained by the certified PANSS rater. CONCLUSIONS: We found a good level of inter-rater reliability of PANSS-6 ratings obtained using the SNAPSI for seven raters with varying levels of clinical and research experience.