The brief psychiatric rating scale: effect of scaling system on clinical response assessment.

The Brief Psychiatric Rating Scale (BPRS) is an 18-item rating scale frequently used to assess change in psychopathology in schizophrenic patients in antipsychotic drug trials. BPRS items may be rated by the use of either a 1 to 7 or 0 to 6 scaling system, with the 1 or 0 rating indicating no pathology, respectively. When percent change in BPRS total score is used as an index of change, measurement considerations indicate that the 0 to 6 scaling system is preferable. Furthermore, when the 1 to 7 scaling system is used, patients whose initial BPRS values fall at the lower end of the range are classified as responders at a lower rate than are patients with higher initial scores. The adoption of the 0 to 6 scaling system for the BPRS and other rating scales, such as the Positive and Negative Syndrome Scale, is advocated.