A global measure to assess switching antipsychotic medications in the treatment of schizophrenia

Abstract

It is common practice to switch antipsychotic medications in the treatment of patients with schizophrenia to enhance clinical efficacy and/or reduce drug-related side effects. The conventional Clinical Global Impression (CGI) of severity scale is a well-understood measure to track switching effects but does not differentiate between the severity of clinical symptoms and the impact of side effects.. We developed a CGI-switch instrument that contains distinct global severity scales for clinical efficacy, safety and/or tolerability, and a third unified (integrated) CGI severity score to assess these interrelated assessments. An integrated Clinical Global Impression of Change was also created to assess global clinical change relative to the initiation of treatment. Interrater reliability conducted as part of a rater-training program for a clinical study (Novartis protocol CIL0522D; clinitrials.gov identifier: CT01207414) revealed high interrater agreement (Cronbach's alpha = 0.945). Data were collected from 1066 CGI assessments during the course of the trial. CGI raters easily grasped the utility of the instrument. The distinction made between efficacy and safety/tolerability facilitated serial tracking of each condition during the course of treatment. The modified CGI-switch instrument is a simple, reliable, and practical metric to assess the benefits, if any of switching antipsychotic medications in patients with schizophrenia.