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

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.

[1]  G. A. Miller.  THE PSYCHOLOGICAL REVIEW THE MAGICAL NUMBER SEVEN, PLUS OR MINUS TWO: SOME LIMITS ON OUR CAPACITY FOR PROCESSING INFORMATION 1 , 1956 .

[2]  D. Streiner,et al.  Health Measurement Scales: A practical guide to thier development and use , 1989 .

[3]  R. Brook,et al.  Consensus methods: characteristics and guidelines for use. , 1984, American journal of public health.

[4]  Barbara L. Welther,et al.  The impact , 1995 .

[5]  J. Fermanian.  [Measuring agreement between 2 observers: a quantitative case]. , 1984, Revue d'epidemiologie et de sante publique.

[6]  D. Cicchetti,et al.  Reliability of depression and associated clinical symptoms. , 1983, Archives of general psychiatry.

[7]  P. Bech.  Rating scales for affective disorders: their validity and consistency. , 1981, Acta psychiatrica Scandinavica. Supplementum.

[8]  L. Kay,et al.  The Impact of "Phenomenology" on North American Psychiatric Assessment , 2003 .

[9]  J. Lee,et al.  Are body mass indices interchangeable in measuring obesity-disease associations? , 1984, American journal of public health.

[10]  J. Rabe-Jabłońska,et al.  [Affective disorders in the fourth edition of the classification of mental disorders prepared by the American Psychiatric Association -- diagnostic and statistical manual of mental disorders]. , 1993, Psychiatria polska.

[11]  M. Ruggeri,et al.  Methodology of a multi-site reliability study , 2000, British Journal of Psychiatry.

[12]  D. Cicchetti,et al.  Developing criteria for establishing interrater reliability of specific items: applications to assessment of adaptive behavior. , 1981, American journal of mental deficiency.

[13]  Peter B. Jones,et al.  The Clinical Global Impression–Schizophrenia scale: a simple instrument to measure the diversity of symptoms present in schizophrenia , 2003, Acta psychiatrica Scandinavica. Supplementum.

[14]  J. Fleiss,et al.  Intraclass correlations: uses in assessing rater reliability. , 1979, Psychological bulletin.

[15]  A. Colman,et al.  Optimal number of response categories in rating scales: reliability, validity, discriminating power, and respondent preferences. , 2000, Acta psychologica.

[16]  G. Regehr,et al.  Methodological problems in the retrospective computation of responsiveness to change: the lesson of Cronbach. , 1997, Journal of clinical epidemiology.

[17]  Eli P. Cox,et al.  The optimal number of response alternatives for a scale: A review. , 1980 .

[18]  M. Mazis,et al.  Determinants of scale response: Label versus position. , 1978 .

[19]  G. Klerman,et al.  A comparison of symptom determinants of patient and clinician global ratings in patients with panic disorder and depression. , 1993, Journal of clinical psychopharmacology.

[20]  Robert M. Post,et al.  Modification of the Clinical Global Impressions (CGI) scale for use in bipolar illness (BP): the CGI-BP , 1997, Psychiatry Research.

[21]  Glenn Regehr,et al.  Delphi as a method to establish consensus for diagnostic criteria. , 2003, Journal of clinical epidemiology.

[22]  J. Guelfi.  Clinical research in psychopharmacology : new standards for drug development. An application to antidepressants , 1990 .

[23]  D. Hunter,et al.  Qualitative Research: Consensus methods for medical and health services research , 1995 .

[24]  J. Levine,et al.  Research and methodological issues for evaluating the therapeutic effectiveness of antidepressant drugs. , 1984, Psychopharmacology bulletin.