Assessing dimensional and categorical aspects of depression: Validation of the AMDP Depression Scale

Background: A new observer depression scale which is based on the descriptive operationalized classification principles of ICD-10 is introduced. The AMDP Depression Scale (AMDP-DS), a 22-item clinician-rated inventory, provides the opportunity of dimensional as well as categorical depression severity assessment. Methods: A sample of 50 patients with depressive symptoms were assessed with the AMDP-DS by two raters in a joint rater session. A number of widely used depression scales were applied separately by an independent rater. The ICD-10 symptom checklist was used for categorical assessment of depressive disorders. Results: The inter-rater reliability for the total score of the AMDP-DS was excellent (Intraclass coefficient: 0.97). There were high correlations with the sum scores of the other scales under study. The correlations between the ICD-10 symptom-checklist and the AMDP-DS ranged from 0.75 to 0.89 for the total sample and 0.44 to 0.51 for patients with acute depressive episode. Limitations: The results are limited by the method of a joint rater setting and the relatively small subsample of patients with depressive episode. Conclusions: The AMDP-DS satisfies the requirements of psychometric criteria with a sufficient degree. A new depression scale designed to cover dimensional as well as categorical aspects has successfully been developed.