title: Recommendations to improve the positive and negative syndrome scale (PANSS) based on item response theory.
abstract: The adequacy of the Positive and Negative Syndrome Scale (PANSS) items in measuring symptom severity in schizophrenia was examined using Item Response Theory (IRT). Baseline PANSS assessments were analyzed from two multi-center clinical trials of antipsychotic medication in chronic schizophrenia (n=1872). Generally, the results showed that the PANSS (a) item ratings discriminated symptom severity best for the negative symptoms; (b) has an excess of "Severe" and "Extremely severe" rating options; and (c) assessments are more reliable at medium than very low or high levels of symptom severity. Analysis also showed that the detection of statistically and non-statistically significant differences in treatment were highly similar for the original and IRT-modified PANSS. In clinical trials of chronic schizophrenia, the PANSS appears to require the following modifications: fewer rating options, adjustment of 'Lack of judgment and insight', and improved severe symptom assessment.
authors.affiliation: Bar Ilan University, Ramat Gan 52900, Israel. levins@biu.ac.il
authors.forename: Stephen Z
authors.initials: SZ
authors.lastname: Levine
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rabinowitz
authors.forename: Dimitris
authors.initials: D
authors.lastname: Rizopoulos
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis*; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014894:Weights and Measures; D055815:Young Adult