Symptom dimensions in recent-onset schizophrenia and mania: a principal components analysis of the 24-item Brief Psychiatric Rating Scale.

Previous four- and five-factor solutions of the 18-item Brief Psychiatric Rating Scale (BPRS) suggested the possibility of an affective dimension in psychosis. A principal components analysis was used to analyze psychiatric symptom data rated on an expanded 24-item version of the BPRS. BPRS data were collected during a period of acute psychotic and affective illness with 114 young adult, recent-onset schizophrenia and schizoaffective patients and 27 bipolar manic patients. Principal components analyses of the 18-item and 24-item BPRS indicated a four-factor solution was the most interpretable. Principal components analysis of the 24-item BPRS produced a clear mania factor characterized by high loadings from items added to the 18-item BPRS, which included elevated mood, motor hyperactivity, and distractibility. This factor solution suggests that the 24-item BPRS allows for an expanded assessment of affective symptoms relating to a manic dimension. Potentially important symptoms that were added to the traditional 18-item version, namely suicidality, bizarre behavior, and self-neglect, also make clear contributions to other factors.