Development of a Korean Version of the Perceived Deficits Questionnaire-Depression for Patients with Major Depressive Disorder

Cognitive symptoms are an important component of depression and the Perceived Deficits Questionnaire-Depression is one of only a few instruments available for the subjective assessment of cognitive dysfunction in depression. Thus, the present study aimed to validate a Korean version of the PDQ-D (K-PDQ-D) using patients with major depressive disorder (MDD). This study included 128 MDD patients who were assessed at study entry and 86 of these patients were then completed 12 weeks of antidepressant monotherapy. All subjects were assessed with the K-PDQ-D, the Montgomery-Asberg Depression Rating Scale (MADRS), the Sheehan Disability Scale (SDS), the EuroQol-5 dimensions questionnaire (EQ-5D), and the number of sick leave days taken in the previous week. The internal consistency, Guttman's split-half and test-retest reliabilities, factorial analyses, and concurrent and predictive validities of the K-PDQ-D were investigated. The K-PDQ-D exhibited excellent internal consistency and reliabilities, and was composed of four factors with high coefficients of determination. The concurrent validity analyses revealed that the K-PDQ-D scores were significantly correlated with the MADRS, SDS, and EQ-5D scores and the number of sick leave days taken. The K-PDQ-D scores at study entry significantly predicted changes in sick leave days and EQ-5D score from study entry to the 12-week endpoint. The newly developed K-PDQ-D is a reliable and valid instrument for the evaluation of subjective cognitive symptoms in MDD patients. The K-PDQ-D may assist in the gathering of unique information regarding subjective cognitive complaints, which is important for the comprehensive evaluation of patients with MDD.