Abstract
Objective: There is a need for a valid measure of depression in the medically ill, and one that is independent of medical illness characteristics. As yet, there is no such widely accepted measure. We thus report on the early development of such a measure using cognitive constructs that define depressive mood state nuances.
Method: We studied 67 patients with a significant medical illness, verbally administering a set of 81 provisional items. Sample members also alternatively completed one of two comparison measures: the Hospital Anxiety and Depression Scale (HADS) or the Beck Depression Inventory for Primary Care (BDI-PC). A psychiatrist interviewed a subset to determine severity of any depression and whether subjects met formalized caseness criteria for depression. The Composite International Diagnostic Interview (CIDI) was also administered during interviews to assess agreement with psychiatrist judgements about caseness.
Results: A 16-item measure with high internal consistency was derived, with validation analyses suggesting it was distinctly superior to the HADS and somewhat superior to the BDI-PC measure.
Conclusions: A cognitive-based approach (as used by both our measure and the BDI-PC) to screen for depression in medically ill groups appears to have distinct utility in identifying depressed patients, and in avoiding confounding influences of physical symptoms.