Concise assessment for depression (CAD): a brief screening approach to depression in the medically ill

Diagnosis of depression in the medically ill is problematic because many of the symptoms used for diagnosis, such as poor sleep and poor appetite, may be due to the underlying physical illness. The aim of the present study was to validate a brief measuring instrument, the concise assessment for depression (CAD), designed to accurately diagnose major depressive disorders in medically ill patients. The CAD was validated against DSM-IV and ICD-10 diagnostic criteria, as well as against modified DSM-IV diagnostic criteria that excluded somatic items. The modified DSM-IV diagnostic criteria have previously been suggested as the most appropriate to use in the medically ill. The effectiveness of the CAD was also compared to the Hospital Anxiety and Depression scale (HAD), a questionnaire widely used to determine the presence of depression in the medically ill. Diagnoses were obtained using a new semistructured psychiatric interview, the Schedules for assessment in Neuropsychiatry (SCAN). A total of 313 consecutive acute medical admissions were interviewed on the 7th day of admission. The first 153 patients also completed the HAD. Using the modified DSM-IV criteria 18 (5.1%) of the patients were diagnosed as having a major depressive disorder. Using a cut-off point of 3, the sensitivity of the CAD for major depressive disorder was 100%, the specificity was 99%, and the positive predictive value was 86%. This compared favorably with the HAD, in which the sensitivity was 78%, the specificity was 77%, and the positive predictive value was 18% using the most favorable cut-off point. The results from the present study thus validate the CAD to be effective in accurately diagnosing major depressive disorder in the medically ill.