The validity and sensitivity of PANSS-6 in the clinical antipsychotic trials of intervention effectiveness (CATIE) study

Abstract

It was recently demonstrated in acutely exacerbated schizophrenia that a 6-item version (PANSS-6: P1 = delusions, P2 = conceptual disorganization, P3 = hallucinations, N1 = blunted affect, N4 = social withdrawal, N6 = lack of spontaneity/flow of conversation) of the 30-item Positive and Negative Syndrome Scale (PANSS-30) was scalable (all items provide unique information regarding syndrome severity) and able to separate the effect of antipsychotics from placebo. Here, we tested the validity and sensitivity of PANSS-6 in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) outpatient study. We examined (1) the scalability of PANSS-6 and PANSS-30; (2) the correlation between PANSS-6 and PANSS-30 total scores; (3) whether PANSS-6 could identify symptom remission (Andreasen criteria); and (4) the effect of the 5 antipsychotics studied in CATIE Phase-1, using PANSS-6 and PANSS-30 total scores as outcomes. We found that for the 577 subjects with complete PANSS ratings at baseline, month 1, 3, and 6, PANSS-6 was scalable, whereas PANSS-30 was not. In the 1432 subjects in the intention-to-treat (ITT) sample, PANSS-6 and PANSS-30 total scores were highly correlated (Spearman correlation coefficient = 0.86). Based on 5080 ITT ratings, PANSS-6 identified symptom remission with an accuracy of 0.99 (95% confidence interval = 0.99–0.99). In ITT analyses, PANSS-6 and PANSS-30 identified the same statistically significant differences in antipsychotic efficacy, ie, olanzapine was superior to risperidone (P-value PANSS-6 = 0.0003 and PANSS-30 = 0.0003) and ziprasidone (P-value PANSS-6 = 0.0018 and PANSS-30 = 0.0046). In conclusion, PANSS-6 is a brief schizophrenia rating scale that adequately measures severity, remission, and antipsychotic efficacy related to core positive and negative symptoms in clinical trials. Prospective studies of PANSS-6 in clinical practice are required.