Internal consistency, convergent validity and reliability of a brief questionnaire on disordered eating (DEQ).

Clinical interviews are considered the gold standard for the evaluation of the specific psychopathology associated with eating disorders. However, there are situations in which brief but valid and reliable self-report questionnaires can be helpful. For this reason, we have developed a new questionnaire, called the DEQ (Disordered Eating Questionnaire), brief enough to be used in epidemiological screenings, that evaluates the frequency and intensity of disordered eating attitudes and behaviours within a time frame of three months and addresses face valid questions to the general population. The aim of this study was to evaluate the dimensionality, reliability and convergent validity of this questionnaire. The DEQ was filled in by Italian secondary school girls and boys, together with the Contour Drawing Rating Scale (CDRS) and with the Eating Attitudes Test (EAT-26). The results showed a single component that explain a portion of variance of around 36%. The reliability of the scale is highly satisfactory. The scale is also valid, since scores on the DEQ scale are significantly and highly correlated with body dissatisfaction, measured by the CDRS, with body mass inex (BMI) and with all the subscales of the EAT-26. As expected, there were gender differences, given that DEQ scores were higher in females than in males.