2.4.2. Depression
depression, depressive
DISORDERS
The Korean version of the Patient Health Questionnaire-9 (PHQ-9) was used to measure the level of depression. The PHQ-9 is a depression scale based on the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition. The scale consists of a total of nine items scored on a four-point Likert scale (0–3), with 3 indicating “almost every day” and 0 indicating “never”. The total score is 27 points, with a higher score indicating more severe depressive symptoms. The scale’s reliability was assessed as high, with a Cronbach’s alpha of 0.80, with the same findings in this study (Cronbach’s α = 0.80).