Abstract
The Inventory of Depressive Symptomatology (IDS) is a rating scale for depression, widely used in international multicentre studies. There are two corresponding versions: a self-rated (IDS-SR) and a clinician-rated (IDS-C) scale. The aim of this study was to evaluate the reliability and validity of the German versions of the IDS-SR and IDS-C in comparison to the Hamilton Rating Scale for Depression (HRSD) and to the Beck Depression Inventory (BDI). The sample consisted of 59 inpatients and outpatients treated for unipolar or bipolar disorders. Internal consistency of the IDS-SR and IDS-C was found highly acceptable (alpha = 0.94 and alpha = 0.93). Item-total-correlations of the IDS-SR revealed that 68% of the items were strongly correlated with the sum score (> or =0.50). This was in the same range with the IDS-C (54%), the HRSD (53%) and the BDI (76%). Furthermore, there is a high concurrent validity (r > or = 0.88) of the IDS-SR with the IDS-C, the BDI and the HRSD. Substantial score-differences between inpatients and outpatients indicate a good discriminant validity. It is concluded that the German version of the IDS is a useful instrument for the assessment of depressive symptoms and that it has the same highly acceptable psychometric properties as the original English version.