Meta-analysis of the Brief Psychiatric Rating Scale - Expanded (BPRS-E) structure and arguments for a new version

The factor structure of the 24 item BPRS-E was examined to determine the effect of additional items on consensus scales derived primarily from the 18 item BPRS. A meta-analysis (k = 32, n = 10,084) of previous factor analyses of the BPRS-E was conducted using both a co-occurrence similarity matrix and reproduced correlations. Components generally supporting the consensus scales were found suggesting four relatively invariant subscales: Affect (defined by the core items: anxiety, guilt, depression, suicidality), Positive Symptoms (hallucinations, unusual thought content, suspiciousness, grandiosity), Negative Symptoms (blunted affect, emotional withdrawal, motor retardation) and Activation (excitement, motor hyperactivity, elevated mood, distractibility). The additional BPRS-E items primarily contribute directly to a clear Activation dimension which expands and clarifies the traditional 18 item BPRS structure. Though not statistically supported in this meta-analysis, a fifth factor describing disorganization (conceptual disorganization, disorientation, self-neglect, mannerisms-posturing) was present in some analyses and should be considered. The five factor solution including a disorganization factor has theoretical validity based on the pentagonal model of schizophrenia while also containing the same four primary dimensions that were statistically supported in this meta-analysis. A new version of the BPRS (BPRS-26) with modified and additional items is presented. BPRS-26 is supposed to enhance the stability and the comprehensiveness of the scale and to more closely measure this five factor model.