Background: Patients with chronic medical diseases may have depression that is not recognized by their primary care physicians.
Objectives: We aimed to examine the application of Zung's Self-Rating Depression Scale (SDS) in the screening of depression in primary care patients with chronic medical diseases in a Chinese population.
Methods: We studied 268 patients with chronic medical diseases in the Family Medicine Outpatient Clinic using a structured questionnaire including basic demographic data, a Chinese version of the SDS and a rating for the self-perceived severity of physical condition. The severity of chronic medical diseases was assessed by the authors using the Duke University Severity of Illness Scale from a chart audit. Fifty patients were randomly selected for a diagnostic interview according to the DSM-IV criteria. The construct validity and internal consistency reliability, sensitivity and specificity of the SDS were examined.
Results: The results revealed that the SDS has good construct validity and internal consistent reliability in the evaluation of depression in Chinese patients with chronic medical diseases. A cut-off point of 55 had a sensitivity of 66.7% and a specificity of 90.0%. Depressed patients reported more cognitive symptoms than depressed affect and physical symptoms. Female patients had more severe depressed affect than male patients, but males had more prominent diurnal variation of mood than females.
Conclusions: We concluded that SDS can be a good screening tool for depression in Chinese patients with chronic medical diseases. Owing to constraints in the expression of sexual desire in the Chinese, elderly subjects tended to report loss of libido in the response to the SDS.