中文版飲食障礙問卷之信度和效度研究

Reliability and Validity of the Mandarin Chinese Version of Eating Disorder Inventory

本研究的目的為建立中文版飲食障礙問卷（Chinese version of Eating Disorder Inventory,簡稱 EDI-1），並進行其信度和效度研究。本研究對象取樣有四組樣本，包括341位大學生（183位女性和158位男性）、69位飲食障礙症、20位已恢復的飲食障礙症以及63名肥胖症；分別施測飲食障礙問卷及其他量表如暴食問卷、視覺量表和簡式症狀量表，以進行信度和效度分析。飲食障礙問卷中各分量表的Cronbach's alpha值都超過或接近0.7，經過項目分析，刪除其與總分間相關較低之項目後，cronbach's alpha值還可提高。臨床診斷組和大學女生組在飲食障礙問卷各分量表的得分上都有顯著差異；臨床診斷組和恢復組在多項分量表得分上亦有顯著差異，和臨床發現相一致。從各分量表和其 他量表的相關亦證明中文版飲食障礙問卷有不錯的幅合效度和辨別效度。飲食障礙問卷使用在飲食障症有良好的內部一致性信度和效度，可測量飲食障礙症多面向的精神病理，但是使用在厭食症者，其身體不滿意分量表得分和暴食症及肥胖症比較起來偏低，而和大學生組相近。各分量表在病人組得分分怖的變異量大，BD分量表和體重成正相關，以及其他因素如厭食症病人的否定作用和跨文化使用的問題等都會影響分量表的得分，使用時應熟悉此問卷的性質，小心判讀其結果。

To establish the Mandarin Chinese Version of Eating Disorder Inventory (EDI), proceed it's reliability and validity test and to address the psychometric properties of EDI in Taiwanese eating disorders patients and university students. Methods: After getting the permission agreement from the copyright owner of EDI (Psychological Assessment Resources. Inc), the EDI was translated into Mandarin Chinese via two-step procedure. The study subjects included 4 groups of persons: university students (N=341, 183 women and 154 men), clinical patients fulfilled DSM-IV eating disorders diagnoses (N=69, 19 AN and 50 BN), recovered eating disorders patients (N=20), and obese patients (N=63). Reliability (internal consistency) and construct validity were established by Cronbach's α method and item-total correlation. The scores between groups were compared by Student's t-test or One way ANOVA. Correlation analyses were used between all EDI subscales and other self-rating scales, e.g. Bulimic Investigatory Test, Edinburgh (BITE), Visual Analogue Scale (VAS) for body weight/ shape and general appearance dissatisfaction, and Brief Symptom Rating Scale (BSRS). Results: Cronbach's alpha values were above or near 0.7 on all subscales and EDI for both female students and clinical patients. The item-subtotal correlation coefficients were below 0.3 for 4 items (item 1, 6, 22 and 43). To delete item 1 may markedly improve internal consistency and construct validity of Drive for Thinness (DT) subscale. Eating disordered patients as well as BN patients were differentiated from female students on all EDI subscales. However, Body Dissatisfaction (BD) subscale can't differentiate effectively between AN patients and female college students. Clinically recovered patients scored similarly to female students on all subscales, and scored lower than eating disordered patients on all subscales except Interpersonal Distrust (ID) and Maturity Fears (MF), which was compatible with the characteristics of recovered patients in the follow-up studies of eating disorders. Convergent validity and discriminate validity were established for all subscales, Group comparison showed BN patients scored higher than AN patients on DT, B and BD subscales but not on the subscales measuring general psychopathology. Obese patients can be well differentiated with AN and BN patients except BD subscale. As expected, the binge-eating/purging AN patients scored higher than the restrictive AN patients only on Bulimia subscale. But the binge-eating/purging AN patients scored lower than BN patients on BD subscale, but higher on MF subscale. The above findings were partially explained by the positive correlation between BD score and percentage of standard body weight (γ-0.40, P<0.001) as well as the heterogeneity of AN and BN groups (evidenced by the large standard deviations compared to means on all subscales). The other possible reasons were denial of illness in AN patients and cultural difference in phenomenology of AN. We defined high DT group as the female students who scored at or above the eating disordered patients’ mean score of 12 on the DT subscale of the EDI (N=26, 14.2%). The high DT group scored higher than eating disorder patients on DT (P<0.01) and BD (p=0.05) subscale, but lower on B. I. IA (p<0.001) and ID (p<0.01) subscales. Conclusions: The Mandarin Chinese Version of Eating Disorder Inventory had satisfactory internal reliability and validity. It can be applied to measure the multidimensional psychopathology of Taiwanese eating disordered patients. However, it did not differentiate the AN patients and female students effectively. We need to be aware the multidetermined nature of EDI-I when apply it to both clinical and general population.