The role of questionnaires is important in improving the recognition of major depression.
Our aims were: 1) to compare the differences of structure between the Depression Scale (DEPS) and other instruments, and 2) to study whether the DEPS items function in the same way with patients grouped by gender, by age or by education, at the same time taking into account the level of depression.
The item topics of the DEPS and five other self-rating questionnaires (BDI-II, CES-D, HADS-D, PHQ-9, SCL-90-D), an interviewer rating scale (HAMD-17) and two diagnostic interviews for depression (ICD-10, DSM-IV) were listed in a table. The format of the questionnaires and the rating scale were compared. Differential item functioning (DIF) analysis using empirical material (n=1522) and logistic regression models was done to predict DEPS item responses across dichotomous categories for gender, age and education.
The DEPS scale items covered essential symptoms of depression. Of the instruments assessed, the DEPS seemed the most simple. DIF analyses with the DEPS scale revealed some socio-demographic variation in which symptoms were endorsed after matching for DEPS sum score. Clinically the DEPS has good applicability and accuracy for screening depression in working aged primary care patients.