Depression was evaluated using the PHQ-9, which is a selfreport scale of depressive symptoms. The PHQ-9 consists of nine items reflecting almost exactly the nine diagnostic criteria for MDD in the DSM-IV. The nine items in the PHQ-9 ask about the frequency of depressive symptoms over the previous two weeks, and each is scored as 0 points for “Not at all,” 1 point for “Several days,” 2 points for “More than half the days,” or 3 points for “Nearly every day.” Thus, the highest possible total score is 27 points. The Korean PHQ-9 was standardized in the general elderly population by Han et al. [19 (link)] and in a primary care setting by Choi et al. [20 ]
Item 9 in the PHQ-9 asks, “Over the last 2 weeks how often have you been bothered by this problem: thoughts that you would be better off dead or hurting yourself in some way?” The PHQ-8, which has been used in numerous previous studies [11 (link),13 (link),21 (link)], excludes Item 9 from the PHQ-9 but retains the other eight items unchanged.
The extent of depressive symptoms was evaluated by a clinical psychologist using the HAMD, which is a clinician-administered scale of depressive symptoms [22 (link)]. It was originally developed for measuring severity in patients already diagnosed with MDD, but its uses have since expanded, including in research to evaluate the effects of treatment, and it is currently considered the standard for observer rating scales for depression. The original scale consisted of 21 items, but the four items regarding diurnal variation, depersonalization-derealization, paranoid symptoms, and obsessive-compulsive symptoms, respectively, are not only rare in patients with depression but were also found to reduce internal consistency. Therefore, the 17-item version, which omits these items, is currently the most widely used version [23 (link)]. In this study, we used the Korean adaptation of the 17-item version of the HAMD, standardized by Yi et al. [24 ]
Item 9 in the PHQ-9 asks, “Over the last 2 weeks how often have you been bothered by this problem: thoughts that you would be better off dead or hurting yourself in some way?” The PHQ-8, which has been used in numerous previous studies [11 (link),13 (link),21 (link)], excludes Item 9 from the PHQ-9 but retains the other eight items unchanged.
The extent of depressive symptoms was evaluated by a clinical psychologist using the HAMD, which is a clinician-administered scale of depressive symptoms [22 (link)]. It was originally developed for measuring severity in patients already diagnosed with MDD, but its uses have since expanded, including in research to evaluate the effects of treatment, and it is currently considered the standard for observer rating scales for depression. The original scale consisted of 21 items, but the four items regarding diurnal variation, depersonalization-derealization, paranoid symptoms, and obsessive-compulsive symptoms, respectively, are not only rare in patients with depression but were also found to reduce internal consistency. Therefore, the 17-item version, which omits these items, is currently the most widely used version [23 (link)]. In this study, we used the Korean adaptation of the 17-item version of the HAMD, standardized by Yi et al. [24 ]
