Reliability of a standardized and expanded Brief Psychiatric Rating Scale: a replication study

This study aimed to determine the replicability of the interrater reliability coefficients obtained with a standardized and expanded Brief Psychiatric Rating Scale (BPRS-E) in a 1991 psychometric evaluation. Furthermore, intrarater reliability was assessed. At item level, interrater concordance turned out to be satisfactory for most of the BPRS-E items. However, only a few of the items reached acceptable chance-corrected coefficients. In contrast to the previous study, the anxiety-depression subscale met the standard of acceptable interrater reliability in the present study. As in the 1991 study, the 10-item psychotic disintegration scale as well as BPRS-18 global scores met (or closely approximated) this standard. The 6 additional items of BPRS-E did not contribute to the scale's reliability. Joining the samples of the 1991 and replication studies (to cover the range of symptoms' severity and heterogeneity more fully) did not improve interrater reliability. Intrarater reliability coefficients were globally comparable to interrater reliability coefficients. In all, the results of this replication study suggest that only the anxiety-depression subscale, the 10-item psychotic disintegration scale and the BPRS-18 global scale can be used reliably in unselected groups of psychiatric inpatients in acute distress.