Quality of Life in Bipolar Disorder: Portuguese validation of the Brief QoL.BD questionnaire

Abstract

The Brief Quality of Life in Bipolar Disorder (Brief QoL.BD) questionnaire is a short version of the first disorder-specific scale developed for Bipolar Disorder (BD), the QoL.BD, designed for use in research settings. This questionnaire has been considered a useful measure to assess psychological interventions’ improvements. This study aimed to validate and assess the psychometric properties of the Brief QoL.BD. Method: The Brief QoL.BD questionnaire was translated to Portuguese according to international guidelines, and participants with BD, psychiatrists and psychologists were consulted regarding its intelligibility. It was then administered to 110 people with BD (M = 43.81 ± 11.72, 66.4% ♀; 33.6% ♂), in addition to other self-report questionnaires, to assess satisfaction with life, anxiety, depression, external shame and positive and negative affect. Results: The Brief QoL.BD revealed good internal consistency (a = .84). Positive correlations with satisfaction with life and positive affect supported the scale’s convergent validity. Significant negative correlations supported the divergent validity with negative affect, depression, anxiety and external shame. Confirmatory factor analysis validated the original one-factor structure showing a good fit. Conclusion: The Portuguese translation of Brief QoL.BD questionnaire (European) proved to be a valid, and reliable quality of life measure to be used with people with bipolar disorder. BD type II displayed significantly lower levels of QoL than type I. Brief QoL.BD is short and easy to apply, being recommended for research purposes, specifically tracking psychological intervention’s impact.