Purpose: Depression is a highly prevalent, morbid, and costly illness that is often unrecognized and inadequately treated. Because depression questionnaires have the potential to improve recognition, we evaluated the accuracy and effects on primary care of two case-finding instruments compared to usual care.
Subjects and methods: The study was conducted at three university-affiliated and one community-based medical clinics. Consecutive patients were randomly assigned to be asked a single question about mood, to fill out the 20-item Center for Epidemiologic Studies Depression Screen, or to usual care. Within 72 hours, patients were assessed for Diagnostic and Statistical Manual of Mental Disorders Third Revised Edition (DSM-III-R) disorders by an assessor blinded to the screening results. Process of care was assessed using chart audit and administrative databases; patient and physician satisfaction was assessed using Likert scales. At 3 months, depressed patients and a random sample of nondepressed patients were re-assessed for DSM-III-R disorders and symptom counts.
Results: We approached 1,083 patients, of whom 969 consented to screening and were assigned to the single question (n = 330), 20-item questionnaire (n = 323), or usual care (n = 316). The interview for DSM-III-R diagnosis was completed in 863 (89%) patients; major depression, dysthymia, or minor depression was present in 13%. Both instruments were sensitive, but the 20-item questionnaire was more specific than the single question (75% vs 66%, P = 0.03). The 20-item questionnaire was less likely to be self-administered (54% vs 90%) and took significantly more time to complete (15 vs 248 seconds). Case-finding with the 20-item questionnaire or single question modestly increased depression recognition, 30/77 (39%) compared with 11/38 (29%) in usual care (P = 0.31) but did not affect treatment (45% vs 43%, P = 0.88). Effects on DSM-III-R symptoms were mixed. Recovery from depression was more likely in the case-finding than usual care groups, 32/67 (48%) versus 8/30 (27%, P = 0.03), but the mean improvement in depression symptoms did not differ significantly (1.6 vs 1.5 symptoms, P = 0.21).
Conclusions: A simple question about depression has similar performance characteristics as a longer 20-item questionnaire and is more feasible because of its brevity. Case-finding leads to a modest increase in recognition rates, but does not have consistently positive effects on patient outcomes.