Development of a psychosocial functioning questionnaire for patients with major depressive disorder

BACKGROUND: The importance of psychosocial functioning in the assessment, diagnosis and treatment of major depressive disorder (MDD) is widely recognised. However, there is a lack of effective scales to assess psychosocial functioning in patients with MDD. AIMS: To develop a professional questionnaire to evaluate the psychosocial functioning of patients with MDD. METHODS: Using a literature review, an open-ended questionnaire survey, and patient interviews, a theoretical model of psychosocial functioning was constructed, and an initial questionnaire was formed which included four dimensions. After two rounds of testing, using items analysis and exploratory factor analysis, a finalized questionnaire was created. There were 460 patients with MDD selected from six psychiatric hospitals for formal testing using a convenience sampling method. Forty patients were randomly selected and retested one week later to evaluate the test-retest reliability of the scale. The Patient Health Questionnaire-9 (PHQ-9), Short Form of Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q-SF), Sheehan Disability Scale (SDS), and Dysfunctional Attitudes Scale (DAS) provided major standards to check the criterion validity of this questionnaire. Correlation analysis, confirmatory factor analysis, and internal consistency reliability testing were used to examine other psychometric characteristics of the finalized questionnaire. RESULTS: The Psychosocial Functioning Questionnaire (PFQ) for patients with MDD included three dimensions: psychological cognitive functioning, subjective well-being, and social functioning, with a total of 18 items. The overall internal consistency reliability of the questionnaire was 0.957, and the test-retest reliability was 0.840. Confirmatory factor analysis showed that the model fitted well: Goodness of Fit Index (GFI)=0.888; Root Mean SquareError of Approximation (RMSEA)=0.085. The total score of PFQ was significantly correlated with the total score of PHQ-9, DAS, SDS and Q-LES-Q-SF (|r|=0.599–0.870, p<0.001). CONCLUSIONS: The Psychosocial Functioning Questionnaire has good reliability and validity. It can be used to measure the psychosocial functioning of patients with MDD.