RESUMO
According to Beck's cognitive theory, dysfunctional core beliefs are developed by stressful life experiences. In addition, depressive episodes could be considered as stressful events. Thus, it is assumed that patients with depressive disorder experience beliefs about depression and its outcome, due to repeated episodes of depression. The aim of this study was to develop an instrument for measuring maladaptive beliefs about depression and assess its psychometric features. A three stage approach was used. In the first stage an item pool was developed and its face validity was approved by a focus group. Subsequently, 698 students of Ghazvin University completed Beck Depression Inventory-II and Depression Beliefs Scale [DBS], developed in the previous stage. 433 subjects completed the DBS again after 14 days. In the third stage, in order to assess discriminant validity, 93 subjects in three groups of patients with recurrent major depressive disorder [N=34], patients with first episode of major depressive disorder [N=29], and non-clinical subjects [N=30] participated in sad mood induction task and then completed DBS. Exploratory factor analysis and Varimax rotation identified four factors related to depression, described as "lack of control on depression", "Catastrophizing", "worthlessness", and "incapability". Also, DBS and its subscales showed satisfactory discriminant validity, convergent validity, internal consistency and test-retest reliability. Identified subscales in DBS reflect concepts of Beck's cognitive theory and Teasdale's differential activation hypothesis about relapse in depression. Also, these results provide preliminary evidence about desirable validity and reliability of DBS. However, psychometric properties of the scale should be assessed in patients with other types of depressive disorders such as dysthymia