Chilean experimental version of the State-Trait Depression Questionnaire (ST-DEP): Trait sub-scale (T-DEP)

Abstract

"This instrumental study presents the first validity and reliability data for the Trait subscale (T-DEP) of the Chilean experimental version of the State and Trait Depression Inventory (ST-DEP): Euthymia and Dysthymia. The data were obtained from a sample of 300 university students. The internal consistency values for the TDEP were high (.90). The test-retest values from eight weeks time interval (fifty six days) were elevated (.78). A factorial analysis of the principal components revealed a principal factor for all of the constructed items in this experimental version of the TDEP. The last, promax rotation showed two clear main factors similar in size: negative affectivity (Dysthymia) and positive affectivity (Euthymia). The convergent validity indexes for the Beck Depression Inventory and the Zung Self Rating Depression Scale, were also high, with indexes ranging from .64 to .71. The correlation between State- Trait Anxiety Inventory and the depression scales used in this study was high (between .63 and .78), once again indicating the usual overlapping between anxiety and depression seen in most depression inventories."