The improved Clinical Global Impression Scale (iCGI): development and validation in depression

Alane Kadouri,Emmanuelle Corruble,Bruno Falissard

doi:10.1186/1471-244x-7-7

Abstract

BackgroundThe Clinical Global Impression scale (CGI) is frequently used in medical care and clinical research because of its face validity and practicability. This study proposes to improve the reliability of the Clinical Global Impression (CGI) scale in depressive disorders by the use of a semi-standardized interview, a new response format, and a Delphi procedure.MethodsThirty patients hospitalised for a major depressive episode were filmed at T1 (first week in hospital) and at T2 (2 weeks later) during a 5' specific interview. The Hamilton Depressive Rating Scale and the Symptom Check List were also rated. Eleven psychiatrists rated these videos using either the usual CGI response format or an improved response format, with or without a Delphi procedure.ResultsThe new response format slightly improved (but not significantly) the interrater agreement, the Delphi procedure did not. The best results were obtained when ratings by 4 independent raters were averaged. In this situation, intraclass correlation coefficients were about 0.9.ConclusionThe Clinical Global Impression is a useful approach in psychiatry since it apprehends patients in their entirety. This study shows that it is possible to quantify such impressions with a high level of interrater agreement.

Highlights

The Clinical Global Impression scale (CGI) is frequently used in medical care and clinical research because of its face validity and practicability
The Delphi procedure appears inefficient since the levels of agreement in group 3 are comparable with the levels of agreement in group 2
The level of agreement in group 2' is higher than in group 2

Summary

Introduction

The Clinical Global Impression scale (CGI) is frequently used in medical care and clinical research because of its face validity and practicability. This study proposes to improve the reliability of the Clinical Global Impression (CGI) scale in depressive disorders by the use of a semi-standardized interview, a new response format, and a Delphi procedure. The Clinical Global Impression scale (CGI) is a classic instrument for making global assessments [1]. This scale yields three different measures: 1. Severity of illness (assessment of patient's current symptom severity, referred to here as CGIs), 2. Global improvement (comparison of patient's baseline condition with his/her current condition, referred to here as CGIi), 3.

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Discussion

Conclusion