Depressive symptoms in patients with Alzheimer's disease

OBJECTIVES: A comparison was made between the depressive symptom profiles of thirty patients with Alzheimer's disease (AD) who did not have co-existing depression and thirty patients with major depression who did not have co-existing dementia. The main objective was to identify symptoms common to both disorders and those which may be able to differentiate AD from major depression. METHOD: A sample of patients suffering from either AD (n = 30) or major depression (n = 30) were recruited from a specialist old age psychiatry service. Depressive symptoms were profiled using the Hamilton Depression Rating Scale (HDRS), the Cornell Scale for Depression in Dementia (CSDD) and the Geriatric Depression Scale (GDS). RESULTS: Depressive symptoms were present in AD in the absence of coexistent major depression. Certain depressive symptoms from all the three scales such as sadness, diurnal variation in mood and early or late insomnia were able to differentiate the two disorders with almost 90% accuracy while symptoms such as irritability, retardation and weight loss were common to both and were unable to differentiate the two. CONCLUSION: Depressive symptoms occur in AD when co-existing depression is ruled out. Their recognition has implications for the diagnosis of major depression in these patients.