Item response analysis of the Positive and Negative Syndrome Scale

<p>Abstract</p> <p>Background</p> <p>Statistical models based on item response theory were used to examine (a) the performance of individual Positive and Negative Syndrome Scale (PANSS) items and their options, (b) the effectiveness of various subscales to discriminate among individual differences in symptom severity, and (c) the appropriateness of cutoff scores recently recommended by Andreasen and her colleagues (2005) to establish symptom remission.</p> <p>Methods</p> <p>Option characteristic curves were estimated using a nonparametric item response model to examine the probability of endorsing each of 7 options within each of 30 PANSS items as a function of standardized, overall symptom severity. Our data were baseline PANSS scores from 9205 patients with schizophrenia or schizoaffective disorder who were enrolled between 1995 and 2003 in either a large, naturalistic, observational study or else in 1 of 12 randomized, double-blind, clinical trials comparing olanzapine to other antipsychotic drugs.</p> <p>Results</p> <p>Our analyses show that the majority of items forming the Positive and Negative subscales of the PANSS perform very well. We also identified key areas for improvement or revision in items and options within the General Psychopathology subscale. The Positive and Negative subscale scores are not only more discriminating of individual differences in symptom severity than the General Psychopathology subscale score, but are also more efficient on average than the 30-item total score. Of the 8 items recently recommended to establish symptom remission, 1 performed markedly different from the 7 others and should either be deleted or rescored requiring that patients achieve a lower score of 2 (rather than 3) to signal remission.</p> <p>Conclusion</p> <p>This first item response analysis of the PANSS supports its sound psychometric properties; most PANSS items were either very good or good at assessing overall severity of illness. These analyses did identify some items which might be further improved for measuring individual severity differences or for defining remission thresholds. Findings also suggest that the Positive and Negative subscales are more sensitive to change than the PANSS total score and, thus, may constitute a "mini PANSS" that may be more reliable, require shorter administration and training time, and possibly reduce sample sizes needed for future research.</p

Using and evaluating psychometric measures

This chapter discusses the use and evaluation of psychometric measures. It reviews literature on the assessment of depression to illustrate many of these theoretical and practical issues, common to most areas of research, which require consideration in selecting and evaluating psychometric measures, and highlights several issues in evaluating the performance of psychometric measures.</p

Dependency and self-criticism : individual differences in strategies for negotiating changes in and threats to social rank

The two studies reported in this thesis examine the influence of two depressive personality styles, dependency and self-criticism, on how individuals respond to potentially disruptive events, such as a change in or threat to social rank. The studies used an experimental protocol in which participants were allowed to believe firstly that they outperformed a close friend or were outperformed by a close friend and secondly that friends generally agreed or disagreed with them. Findings offer support for the integration of depressive personality styles and interpersonal factors within a social rank framework. Results from the two studies suggest that dependency and self-criticism (a) moderate the impact of interpersonal events, (b) influence how individuals behave towards close friends, (c) affect how individuals remember interpersonal interactions with others, and (d) moderate the manner in which individuals actively structure their social environments. Depressive personality styles may contribute to maladaptive environments and depressive processes in complex ways by influencing the types of strategies individuals adopt to deal with threats to interpersonal relatedness and self-definition