Development of a questionnaire to assess inter-episode functioning in bipolar disorder: Bipolar disorder functioning questionnaire

Abstract

Objective: Even though quality of life and functioning are topics that are point of interest, they are not assessed adequately in mood disorders. In this study, it is aimed to develop a functioning assessment scale in bipolar disorder.

Method: Bipolar Disorder Functioning Questionnaire (BDFQ) is developed by the Scientific Section for Mood Disorders of the Psychiatric Association of Turkey. The questionnaire contains 58 items, and consists of eleven subscales: emotional functioning, intellectual functioning, sexual functioning, feelings of stigmatization, social withdrawal household relations, relations with friends, participation to social activities, daily activities and hobbies, taking initiative and self sufficiency, and occupation.

Results: In this study, 252 remitted bipolar patients from 15 centers were included. In addition, thirty subjects without any lifetime psychiatric, neurological or physical disease were recruited. The mean age of the patients was 38.6 +/- 12.1 and 56% (n=141) were female. The mean duration of the bipolar disorder was 11.9 +/- 9.2 years, and 91.3% of the patients were diagnosed to have bipolar I disorder. In the reliability analyses, after the exclusion of six items with low reliability coefficients, The Cronbach alpha coefficient was calculated to be 0.91. The item-total scale correlations were between 0.22-0.86. In test-retest reliability, the correlation between the two ratings was high (r=0.82, p<0.0001). In validity analyses, 13 factors were obtained representing 65.1% of the total variance in exploratory factor analysis. In confirmatory factor analysis, 11 domains fit the model with a RMSEA of 0.061. BDFQ significantly correlated with GAF (r=0.428, p<.0001). BDFQ also showed significantly negative correlation with HAM-D (r=-0.541, p<0.0001) and YMRS (r=-0.365, p<0.0001). It discriminated the patients (mean score=111.8 +/- 15.2) from the healthy subjects (mean score=121.4 +/- 10.4) well (t=-2.300, p=0.038).

Conclusion: With the six items excluded, it is suggested that the 52-item BDFQ is a reliable and valid instrument in the assessment of functioning in bipolar disorder.