A direct comparison of effect sizes from the clinical global impression-improvement scale to effect sizes from other rating scales in controlled trials of adult social anxiety disorder

Abstract

Objective: The clinical global impression-improvement scale (CGI-I) is used to monitor treatment outcome in mental disorders. To better understand the properties of the CGI-I scale in social anxiety disorder, effects sizes from the CGI-I scale were compared to comparably calculated effect sizes from other rating scales obtained from double-blind, placebo-controlled trials of selective-serotonin reuptake inhibitors in social anxiety disorder. From peer-reviewed, double-blind, placebo-controlled studies evaluating selective serotonin reuptake inhibitors in social anxiety disorder, we extracted CGI-I data and scores from other assessment scales of severity and function. Using calculations that enabled direct comparisons, effect sizes for the binarily reported CGI-I scores were compared to effect sizes from the quantitative scales. Results: Effect sizes for the binary CGI-I scale were statistically indistinguishable from effect sizes obtained from the other scales, with the exception of the social avoidance and distress scale. Conclusions: The CGI-I scale is an appropriate method of assessing clinical change in trials of social anxiety disorder. Copyright © 2008 John Wiley & Sons, Ltd.