An Optimized Version of the Positive and Negative Symptoms Scale (PANSS) for Pediatric Trials.

OBJECTIVE: The accepted primary outcome measure for evaluating psychotic symptoms is decades old, long, and initially designed for adults. Surprisingly, the psychometric properties of primary outcome measures have never been reported for a pediatric sample using modern methods. The present study's aim is to use a pediatric sample to evaluate the psychometrics of the most used primary outcome measure in pediatric schizophrenia trials, the Positive and Negative Syndrome Scale (PANSS). METHOD: To evaluate the factor structure, item characteristics, and treatment sensitivity of the PANSS in a pediatric sample, secondary analyses of PANSS data at baseline and weekly throughout an 8-week randomized double-blind study of 3 antipsychotic agents (registered and previously published) were conducted. Subjects were 118 youths receiving outpatient psychiatric treatment for schizophrenia spectrum disorders (mean age = 14.26 years, SD = 2.41 years). RESULTS: A 10-item short form, keeping 2 strongest items for each factor, had r = 0.89 with the full-length scale. Each of the five 2-item subscales has alphas ranging from 0.66 to 0.84. Item Response Theory (IRT) found that the 10-item scale and 2-item subscores had high reliability across the severity range typical of those for clinical trials. Criterion validity was high, with equal sensitivity to clinical changes over time. CONCLUSION: A 10-item PANSS version eliminates weaker items in the pediatric population while preserving coverage of 5 factors and similar sensitivity to clinical changes over time. It thus may be more appropriate for subsequent pediatric trials, and for clinical use when time and efficiency are paramount.

Issues in selection of instruments to measure negative symptoms.

Guidance for selection of instruments for measurement of negative symptoms is rapidly evolving. As there are continuing advances in the description of negative symptoms, new instruments are under development, and new data on the performance of instruments emerge from clinical trials. The Scale for Assessment of Negative Symptoms (SANS), the Positive and Negative Syndrome Scale (PANSS), the Marder Negative Factor and the Negative Symptom Assessment-16 (NSA-16) are considered to be reliable and valid measures for negative symptom trials but differ with respect to their domain coverage, use of informants, integration of global scores, administration time and comprehensiveness of their structured interviews. In response to the 2005 NIMH-MATRICS consensus statement, work groups are field testing and refining two new measures, the Clinical Assessment Interview for Negative Symptoms (CAINS) and the Brief Negative Symptom Scale (BNSS). Both address the five currently recognized domains of negative symptoms, differentiate appetitive from consummatory aspects of anhedonia and address desire for social relationships. Thus far, both have exhibited promising psychometric properties.