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Development of the QoL.BD: a disorder-specific scale to assess quality of life in bipolar disorder

Authors

  • Erin E Michalak,

    1. Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
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  • Greg Murray,

    1. Faculty of Life and Social Sciences, Swinburne University of Technology, Hawthorn, Australia
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  • CREST.BD

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    •  The Collaborative RESearch Team to Study Psychosocial Issues in Bipolar Disorder (CREST.BD, http://www.crestbd.ca) is a team of researchers, clinicians, and community members dedicated to developing knowledge on bipolar disorder (BD). The international team includes representatives from a variety of health disciplines, including psychology, psychiatry, occupational therapy, nursing, genetic counseling, and mental health advocacy. A guiding principle of CREST.BD is to foster and promote community-based research, whereby individuals with BD and their family members are active participants in research and knowledge exchange. Team members Raymond Lam and Lakshmi Yatham, Department of Psychiatry, University of British Columbia, and Sheri Johnson, Department of Psychology, University of California, Berkeley, provided access to patients at their respective sites for the psychometric phases of this project. The CREST.BD Community Consultation Group (a cohort of approximately 100 individuals with BD living in British Columbia, Canada) was actively involved in all stages of data collection for this project.


  • The authors of this paper do not have any commercial associations that might pose a conflict of interest in connection with this manuscript.

Corresponding author:
Erin E. Michalak, Ph.D.
Division of Mood Disorders
Department of Psychiatry
University of British Columbia
2255 Wesbrook Mall
Vancouver, BC, Canada V6T 2A1
Fax: +1-604-822-7792
E-mail: erin.michalak@ubc.ca

Abstract

Michalak EE, Murray G, CREST.BD. Development of the QoL.BD: a disorder-specific scale to assess quality of life in bipolar disorder.
Bipolar Disord 2010: 12: 727–740. © 2010 The Authors.
Journal compilation © 2010 John Wiley & Sons A/S.

Background:  There is wide recognition that symptom ratings alone are inadequate to measure outcomes in bipolar disorder (BD), and quality of life (QoL) has been proposed as an important separable construct. Although a literature on QoL in BD exists, there is no disorder-specific measure of QoL in BD. In 2004, we embarked upon a four-year mixed-method program of research to develop such a measure that could function as an outcome tool in clinical trials of pharmacological or psychosocial treatment interventions, longitudinal monitoring, or routine clinical care.

Methods:  The project was informed by standard protocols for the development of disorder-specific QoL measures. Two phases of scale development were pursued across four empirical studies. Item generation involved a qualitative investigation of individuals with BD, family members, and field experts (Study 1), as well as a literature review. Item reduction analyses were conducted using an intensive small-N design with affected individuals (Study 2), a large field sample (Study 3), and a final small-N item reduction study, again involving individuals with the disorder and field experts (Study 4).

Results:  Initial field testing of the Quality of Life in Bipolar Disorder (QoL.BD) scale supports use of the instrument as a feasible, reliable and valid disorder-specific QoL measure for BD. Internal reliability of the QoL.BD is impressive, test-retest reliability is appropriate, and the direction and magnitude of correlations with external measures are as expected. As a new instrument, the QoL.BD must be compared against existing options for measuring QoL in this population. Significantly, data suggest that the greater specificity of the QoL.BD relative to the Quality of Life Enjoyment and Satisfaction Questionnaire renders the new instrument more sensitive to clinical change in BD.

Conclusions:  Quality of life scales can provide important information additional to that provided by traditional assessments of outcome in BD. Our intensive, mixed-method development of the QoL.BD has produced a useful additional measure of well-being for this complex and often disabling condition.

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