A COMPARISON OF INSTRUMENT SENSITIVITY TO NEGATIVE SYMPTOM CHANGE

Accurate assessment of negative symptom changes In schizophrenic patie nts is crucial to determining the efficacy of new treatments, The pres ent study examined the sensitivity to change over the course of hospit alization in negative symptomatology assessed by the Scale for the Ass essment of Negative Symptoms (SANS), the Negative Symptom Assessment ( NSA), and an expanded version of the Brief Psychiatric Rating Scale (B PRS) in a sample of 60 schizophrenic patients. Symptoms were assessed when the patients were acutely ill and again when they were stabilized , Effect sizes were compared across all three rating scales, The retar dation factor of the BPRS had a relatively small effect size (0.32). E ffect size for the total NSA was 0.78 and ranged from 0.38 to 0.87 for the SANS, Individual factors had moderate to large effect sizes that ranged from 0.18 to 0.91 for both scales, Separate analyses were perfo rmed to calculate effect sizes for a five-factor version of the NSA an d to examine only those symptoms specified in DSM-IV (alogia, affectiv e flattening, and avolition). Effect sizes relatively comparable to th ose found for the entire SANS and NSA scales were found for the separa te calculations. Results indicate that the addition of a negative symp tom assessment instrument to research protocols increases the ability to detect changes in negative symptoms with substantially fewer subjec ts than would be required with the BPRS retardation factor alone.