OBJECTIVE: To evaluate the validity and reliability of the 16-item self-report version of the Quick Inventory of Depressive Symptomatology QIDS-SR16 in a Turkish student sample (QIDS-SR16-T) by comparing it to (a) the American version (QIDS-SR16-US) and (b) the Turkish version of the Beck Depression Inventory (BDI-II-T). Our study is a crosscultural validity study of the QIDS inventory between Turkey and the USA.
MATERIAL&METHOD: A slightly modified version of the QIDS-SR16-T, available at www.ids-qids.org, and the BDI-II-T were administered to 626 outpatients at the Uludağ University campus-based family health center in Turkey. The QIDS-SR16âUS was administered to 584 university student respondents at Texas Southwestern University in the USA. SAS and MPlus statistics softwares were used for the statistical analyses, which consisted of descriptive statistics, classical and item response theory analyses, and exploratory factor and multiple group confirmatory factor analyses.
OBJECTIVE: To evaluate the validity and reliability of the Quick Inventory of Depressive Symptomatology, self-reported version, in a Turkish student sample (QIDS-SR16-T) by comparing it to (a) the American version (QIDS-SR16-US) and (b) the Turkish version of the Beck Depression Inventory (BDI-II-T).
MATERIALS & METHODS: Slightly modified versions of the QIDS-SR16-T, and the BDI-II-T were administered to 626 outpatients at the Uludağ University campus-based family health center. The QIDS-SR16âUS was administered to 584 respondents at an American university. SAS and MPlus were used to provide descriptive statistics, classical exploratory factor analysis, and item response theory analyses (in the form of a multiple group confirmatory factor analysis).
RESULTS: The internal consistency (Cronbach ï¡ï© of the QIDS-SR16-T was 0.77. Both QIDS-SR16 versions were unidimensional, but the BDI-II-T was not. The mean QIDS-SR16-T and QIDS-SR16-US item-total correlations were similar. The correlation between the QIDS-SR16-T and BDI-II-T was 0.72 (.90 when disattenuated). Multiple-group confirmatory factor analysis suggested that the QIDS-SR16-T and QIDS-SR16-US had the same factor loadings but different intercepts. This reflects group differences in level of depression, perhaps because the Turkish respondents, unlike their US counterparts, were seen in a medical context where illness-related depression is more prevalent. Scores on the QIDS-SR16-T and the BDI-II-T were also equated.
DISCUSSION: The QIDS-SR16âT has good psychometric properties and convergent validity with the BDI-II-T. Its use is recommended when a self-reported instrument is appropriate.
major depressive episode, screening scale, validity, reliability