Development and validation of a knowledge, attitude and practice questionnaire of personal use of tranquilizers

Background: Tranquilizer misuse is insufficiently acknowledged as a public health problem despite its alarming consequences. Instruments to measure psychosocial factors related to tranquilizer misuse are lacking. We aimed to develop and validate a Knowledge, Attitude and Practice questionnaire of tranquilizer misuse by adults in Spain. Methods: The questionnaire was designed after an extensive literature review and several meetings with experts. We assessed face and content validity, and pilot tested the questionnaire. We examined its reliability by testretest analysis in a sample of 145 adults. We distributed the questionnaire to 879 individuals, tested the construct validity through Confirmatory Factor Analysis (CFA), measured its overall reliability and determined its acceptability. Results: The Item Content Validity Index (I-CVI from 0.78 to 1.00), the Scale Content Validity Index, using the averaging method (S-CVI/Ave = 0.95) and the fact that the modified Kappa statistic for each of the Knowledge, Attitude and Practice items was equal to I-CVI demonstrated the content validity of the questionnaire. The Intra-Class Correlation coefficients for Knowledge and Attitude items were > 0.5, establishing their reliability. The Knowledge and Attitude construct was modeled using CFA and the model showed a good fit, thus establishing its validity. The overall reliability of the construct was revealed by Cronbach's alpha values > 0.6. The questionnaire was highly accepted (response rate = 95 % and item non-response <= 4%). Conclusions: The validity of the developed questionnaire was established. Its availability will stimulate the initiation of research on tranquilizer misuse and will consequently help in designing related public health interventions.