Diagnosis and Treatment of Depression in Patients With Alzheimer's Disease and Other Dementias

Depressive disorders—both major depression and other less severe but nonetheless clinically significantdepressions—are common comorbidities, components, or complications of dementia. Depression with reversiblecognitive impairment may be a prodrome for dementia rather than a separate and distinct disorder.Recent research has demonstrated that both the diagnosis of major depression and the assessment of typicaldepressive symptoms can be conducted reliably, even in patients with mild-to-moderate levels of cognitiveimpairment. Self-ratings of depressive symptoms with the Geriatric Depression Scale remain valid in patientswith Mini-Mental State Examination scores of at least 15. Among interviewer-administered instruments,the Hamilton Rating Scale for Depression and the Cornell Scale are the best established. Potentialdifficulties with assessment include problems with ascertainment (because families, in general, reportgreater depression in patients than do clinicians) and the ambiguity of symptoms (because apathy and relatedsymptoms can result from both depression and Alzheimer’s disease). Brain changes due to Alzheimer’s diseasemay lead to fundamental differences in drug responses. Nevertheless, randomized clinical trials havedemonstrated that depression in dementia responds to specific psychopharmacologic or psychosocial treatments.