Characteristics of Residual Symptoms in Korean Patients with Major Depressive Disorder: A Validation Study for the Korean Version of Depression Residual Symptom Scale

OBJECTIVE: Residual symptoms of depression are related to more severe and chronic course of functional impairment with higher risk of relapse. The objective of this study was to validate, and determine psychometric properties of the Korean version of Depression Residual Symptom Scale (KDRSS). METHODS: A total of 203 outpatients with recent episode of major depression based on DSM-IV criteria were enrolled in this study. They had been treated with antidepressants and assessed by KDRSS, Hamilton Depression Rating Scale-24 (HDRS-24), and Montgomery-Åsberg Depression Rating Scale (MARDS). The validity and reliability of KDRSS were assessed, including internal consistency reliability, concurrent validity, temporal stability, factorial validity, and discriminative validity. RESULTS: Internal consistency (Cronbach’s alpha=0.961), concurrent validity (MADRS: r=0.731, p < 0.01, HDRS-24: r=0.663, p < 0.01), and temporal stability (r=0.726, p < 0.01) of KDRSS were all excellent. KDRSS showed good discriminative validity based on MARDS. KDRSS consisted of one-factor structure accounting for 63.8% of total variance. All subjects except two in full remission group had one or more residual symptoms. In 7 subscales of KDRSS consisting of similar items respectively, ‘lack of energy’ was the most commonly reported, followed by ‘increased emotionalism’ in this group. CONCLUSION: KDRSS is a useful and sensitive instrument for measuring residual depressive symptoms. Since some depressive symptoms including ‘lack of energy’ and ‘increased emotionalism’ in patients with full remission might be persistent during psychiatric intervention, these symptoms need to be focused on in clinical practice.

Can Residual Symptoms During Inter-Episode Period after Partial Remission in Bipolar I Disorder Have Cyclic Patterns with Specific Frequencies?

This case report aimed to describe cyclic patterns of residual mood symptoms in partially remitted bipolar I patient. In a 24-year-old woman with bipolar I disorder, residual mood symptoms measured by self-rated daily mood chart for 18 months were analyzed using wavelet analysis. A 146-day periodicity was prominent for the first 100 days after discharge. Between 100–200 days, 146-day periodicity was progressively diminished and 21- and 8-day periodicity was prominent. Between 200–516 days, 21-day periodicity was diminished and 85-day periodicity became prominent. This case suggest that bipolar patients might have cyclic residual symptoms with specific frequencies.

Measurement-based Treatment of Residual Symptoms Using Clinically Useful Depression Outcome Scale: Korean Validation Study

OBJECTIVE: This study was aimed at evaluating the diagnostic validity of the Korean version of the Clinically Useful Depression Outcome Scale (CUDOS) with varying follow-up in a typical clinical setting in multiple centers. METHODS: In total, 891 psychiatric outpatients were enrolled at the time of their intake appointment. Current diagnostic characteristics were examined using the Structured Clinical Interview for DSM-IV (41% major depressive disorder). The CUDOS was measured and compared with three clinician rating scales and four self-report scales. RESULTS: The CUDOS showed excellent results for internal consistency (Cronbach's α, 0.91), test-retest reliability (patients at intake, r=0.81; depressed patients in ongoing treatment, r=0.89), and convergent and discriminant validity (measures of depression, r=0.80; measures of anxiety and somatization, r=0.42). The CUDOS had a high ability to discriminate between different levels of depression severity based on the rating of Clinical Global Impression for depression severity and the diagnostic classification of major depression, minor depression, and non-depression. The ability of the CUDOS to identify patients with major depression was high (area under the receiver operating characteristic curve=0.867). A score of 20 as the optimal cutoff point was suggested when screening for major depression using the CUDOS (sensitivity=89.9%, specificity=69.5%). The CUDOS was sensitive to change after antidepressant treatment: patients with greater improvement showed a greater decrease in CUDOS scores (p<0.001). CONCLUSION: The results of this multi-site outpatient study found that the Korean version of the CUDOS is a very useful measurement for research and for clinical practice.