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The validity and internal structure of the Bipolar Depression Rating Scale: data from a clinical trial of N-acetylcysteine as adjunctive therapy in bipolar disorder

Published online by Cambridge University Press:  24 June 2014

Michael Berk*
Affiliation:
Department of Clinical and Biomedical Sciences: Barwon Health, The University of Melbourne, Geelong, Australia Orygen Research Centre, Parkville, Australia Mental Health Research Institute, Parkville, Australia
Seetal Dodd
Affiliation:
Department of Clinical and Biomedical Sciences: Barwon Health, The University of Melbourne, Geelong, Australia
Olivia M Dean
Affiliation:
Department of Clinical and Biomedical Sciences: Barwon Health, The University of Melbourne, Geelong, Australia Mental Health Research Institute, Parkville, Australia
Kristy Kohlmann
Affiliation:
Department of Clinical and Biomedical Sciences: Barwon Health, The University of Melbourne, Geelong, Australia
Lesley Berk
Affiliation:
Department of Clinical and Biomedical Sciences: Barwon Health, The University of Melbourne, Geelong, Australia Department of Psychiatry, University of Melbourne, Parkville, Australia
Gin S Malhi
Affiliation:
Academic Discipline of Psychological Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia CADE Clinic, Department of Psychiatry, Royal North Shore Hospital, Sydney, NSW, Australia
*
Michael Berk, Department of Clinical and Biomedical Sciences: Barwon Health, The University of Melbourne, PO Box 281, Geelong 3220, Australia. Tel: +61 3 5260 3085; Fax: +61 3 5246 5165; E-mail: [email protected]

Abstract

Berk M, Dodd S, Dean OM, Kohlmann K, Berk L, Malhi GS. The validity and internal structure of the Bipolar Depression Rating Scale: data from a clinical trial of N-acetylcysteine as adjunctive therapy in bipolar disorder.

Background:

The phenomenology of unipolar and bipolar disorders differ in a number of ways, such as the presence of mixed states and atypical features. Conventional depression rating instruments are designed to capture the characteristics of unipolar depression and have limitations in capturing the breadth of bipolar disorder.

Method

The Bipolar Depression Rating Scale (BDRS) was administered together with the Montgomery Asberg Rating Scale (MADRS) and Young Mania Rating Scale (YMRS) in a double-blind randomised placebo-controlled clinical trial of N-acetyl cysteine for bipolar disorder (N = 75).

Results:

A factor analysis showed a two-factor solution: depression and mixed symptom clusters. The BDRS has strong internal consistency (Cronbach's alpha = 0.917), the depression cluster showed robust correlation with the MADRS (r = 0.865) and the mixed subscale correlated with the YMRS (r = 0.750).

Conclusion:

The BDRS has good internal validity and inter-rater reliability and is sensitive to change in the context of a clinical trial.

Type
Research Article
Copyright
Copyright © 2010 John Wiley & Sons A/S

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