Development, reliability and factor analysis of a self-administered questionnaire which originates from the World Health Organization's Composite International Diagnostic Interview - Short Form (CIDI-SF) for assessing mental disorders

Abstract

Background: The Composite International Diagnostic Interview - Short Form consists of short form scales for evaluating psychiatric disorders. Also for this version training of the interviewer is required. Moreover, the confidentiality could be not adequately protected. This study focuses on the preliminary validation of a brief self-completed questionnaire which originates from the CIDI-SF. Sampling and Methods: A preliminary version was assessed for content and face validity. An intermediate version was evaluated for test-retest reliability. The final version of the questionnaire was evaluated for factor exploratory analysis, and internal consistency. Results: After the modifications by the focus groups, the questionnaire included 29 initial probe questions and 56 secondary questions. The test retest reliability weighted Kappas were acceptable to excellent for the vast majority of questions. Factor analysis revealed six factors explaining 53.6% of total variance. Cronbach's alpha was 0.89 for the questionnaire and 0.89, 0.67, 0.71, 0.71, 0.49, and 0.67, for the six factors respectively. Conclusion: The questionnaire has satisfactory reliability, and internal consistency, and might be efficient for using in community research and clinical practice. In the future, the questionnaire could be further validated (i.e., concurrent validity, discriminant validity). © 2008 Gigantesco and Morosini; licensee BioMed Central Ltd.