How does the ICD-10 symptom rating (ISR) with four items assess depression compared to the BDI-II? A validation study.

Objective: The "ICD-10 Symptom-Rating" (ISR) is a novel 29-item self-rating questionnaire with scales for the assessment of depression, anxiety, OCD, somatisation and eating disorders and additional items. This study aims at the validation of the depression subscale.

Methods: Based on a sample of 1844 depressed inpatients, the ISR was correlated with the Beck-Depression-Inventory-II (BDI-II). To estimate the sensitivity to change, the effect sizes were also calculated.

Results: The correlation between ISR and BDI-II was r=0.79. The sensitivity to change for the BDI-II was d=1.44, for the ISR-depression scale d=1.64.

Limitations: The studied sample shows a higher psychiatric and somatic comorbidity, a lower mean age and a higher level of education than comparable samples from other psychiatric or psychosomatic studies. Although we cannot find any effects of these differences on our results, they cannot be fully dismissed without further study.

Conclusion: The ISR-depression scale correlates highly with the BDI-II. Being more sensitive to change than the BDI-II, the ISR is a useful tool to diagnose and measure the severity and course of depression.