Longitudinal factor structure of the Brief Psychiatric Rating Scale in schizophrenia

The focus of this study was the invariance of the factor structure of the B rief Psychiatric Rating Scale (BPRS) over time. An initial sample of 193 in dividuals diagnosed with nonacute schizophrenia or schizoaffective disorder were administered the BPRS every 6 months over a 3-year period. Multiple-g roups confirmatory factor analysis was used to fit the 4-factor oblique mod el of Mueser, Curran, and McHugo (1997) to both the 16-item and 18-item ver sion of the BPRS. The results show that. the model was configurally invaria nt over time, but it was more invariant for the 16-item version. The findin gs suggest that the factors, Thought Disturbance, Anergia, Affect, and Diso rganized, as measured by the BPRS are distinct symptom constructs that endu re over at least a 3-year period,bur the strength of their interrelationshi ps varies. implications for interpretation of change in observed scores ove r time are discussed.