Use of BPRS-A percent change scores to identify significant clinical improvement: accuracy of treatment response classification in acute psychiatric inpatients

Use of Brief Psychiatric Rating Scale [Overall J.E., Gorham D.R., 1988. The Brief Psychiatric Rating Scale (BPRS): recent developments in ascertainmen t and scaling. Psychopharmacology Bulletin 24, 97-99] percent change scores (PCSs) to measure treatment effects may be problematic because two differe nt item-weighting systems (0-6 and 1-7) have been employed to represent the seven rating options and PCSs have demonstrated sensitivity to the item-we ighting system used. This study compared the ability of a range of BPRS tot al scale PCS categories generated by both item-weighting procedures to pred ict estimates of clinical improvement in a large (N = 1415) heterogeneous a cute sample of adult psychiatric inpatients. Results revealed significant d ifferences between the two scaling systems in the proportion of patients cl assified into categories of PCS symptom improvement. Additional analysis su ggested different optimal predictive PCS classifications for each item-weig hting system: > 19% for 1-7 and > 39% for 0-6. Guidelines for BPRS publicat ions are presented to facilitate study interpretation and replication. In l ight of their demonstrated limitations, it is suggested that the use of BPR S PCSs to measure treatment effects be reconsidered. (C) 1999 Elsevier Scie nce Ireland Ltd. All rights reserved.