Depression is a common occurrence in terminally ill patients. However, because much of the focus is on the primary medical condition, the depression may often go unrecognized by the treating clinician. Methods to screen for depression through patient self-reporting have been developed in an attempt to accurately and quickly identify such patients in the context of a routine office visit. The correlation of these screening interviews with clinician-administered interviews has been less than optimal. Chochinov and colleagues conducted a study to compare the performance of four brief screening measures for depression in a group of terminally ill patients.
A total of 197 patients who were receiving palliative care for advanced terminal cancer were included in the study. The four screening inventories used in the study included the Beck Depression Inventory—Short Form, a visual analog scale, a two-item interview assessing depressed mood and loss of interest or pleasure in activities and a single-item interview assessing depressed mood. The diagnostic interview used specific items pertaining to the diagnosis of major and minor depression from the Research Diagnostic Criteria. A total of 24 patients met the criteria for either major or minor depression (15 patients and nine patients).
The single-item inventory assessing depressed mood correctly identified the eventual diagnostic outcome of every patient in the study group. Whenever a patient acknowledged a depressed mood at a threshold level of severity, the probability of having major or minor depression based on the Research Diagnostic Criteria interview used by the examiners was 100 percent. Patients who did not admit to having a depressed mood were never diagnosed with depression based on the Research Diagnostic Criteria.
If the screening interview was extended to two items, all of the patients who were found to be depressed based on the Research Diagnostic Criteria were correctly identified; however, the two-item scale also identified four patients as depressed who were not classified as such on the basis of the full diagnostic interview. The Beck inventory short form correctly identified about 80 percent of depressed patients. The analog screen was even less accurate, identifying only 72 percent of clinically depressed patients and incorrectly labeling 50 percent of patients as depressed.
The authors conclude that a single-item interview that simply asks, “Are you depressed?” provides a very reliable and accurate screening tool when assessing depressed mood in terminally ill patients. The inclusion of an additional diagnostic criterion for depression such as a loss of interest or pleasure in activities did not improve the diagnostic accuracy of the screening examination. However, it may still be reasonable to include this piece of information in a brief screening interview, since it is considered a core criterion for depression. The overall performance of the one- or two-item interview was far superior to the Beck Depression Inventory and the visual analog scale for assessing depressed mood in terminally ill patients.