Mohammed T. Abou-Saleh

THE ASSESSMENT OF DEPRESSIVE STATES 155and insomnia, although these same symptoms may occur in nondepressseddemented patients if they are too disorganized toprepare a meal or have night-time confusion. Some researchershave pointed to the presence of cognitive symptoms of depression(i.e. depressed mood, anxiety, helplessness, hopelessness andworthlessness) as being more prominent in demented patients,whereas neurovegetative signs are notably absent 31 .Monitoring the patient over time, observing for some overallconsistent pattern of depressed mood and affect, is also helpful.Although there is little or no data to support empiric trials ofantidepressants, given the relatively low side-effect profile of thenewer antidepressants 32 (SSRIs: see Chapter 78), many clinicians willoften attempt a trial of an antidepressant in these difficult situations inhopes the treatment may improve cognition and function.PSYCHOLOGICAL TESTSStandardized assessments of cognitive performance (e.g. WechslerAdult Intelligence Scale and Clinical Dementia Rating Scale 33 )may also be useful in distinguishing depression and dementia. Thedepressed patient will more likely show results that are inconsistentover time and are effort-dependent. The demented patientwill demonstrate a more global decline, with relatively lowerscores on aspects of the testing requiring adaptability andprocessing of information (e.g. performance IQ) as opposed torote skills and long-term memory tasks (e.g. verbal IQ).Standardized depression scales may yield false-positive results indemented patients, particularly if they are heavily weighted fordifficulties symptoms, such as with attention and concentration,which overlap with symptoms of depression. Depression scales thathave been specifically designed to grade levels of depression inpatients known to be demented include the Cornell DepressionScale 34 and the Dementia Mood Assessment Scale 35 . The GeriatricDepression Scale (GDS), Beck Depression Inventory (BDI) and theMontgomery–Asberg Depression Rating Scale (MADRS) are otheruseful tests that can help aid in evaluation of a depressed patient 36–38 .LABORATORY TESTSThe common laboratory tests for depression may lose much oftheir specificity in demented patients. The Dexamet has onesuppression test that is frequently abnormal in dementia 39,40 .The sleep electroencephalogram, however, does maintain itsspecificity and is able to distinguish a group of elderly depressedpatients from those with dementia 41,42 .Any physical illness that can potentially affect the centralnervous system can present with depressive and dementingsymptoms; these illnesses include encephalitis, chronic subduralhematoma and normal pressure hydrocephalus. Depressivesymptoms such as fatigue, insomnia, weight loss and concentrationproblems can occur in other illnesses that do not directlyaffect the central nervous system (CNS). These illnesses includeinfectious diseases (e.g. tuberculosis, influenza), cardiovasculardisease (e.g. congestive heart failure), endocrine abnormalities(e.g. thyroid disease, diabetes), electrolyte disturbances (e.g.hyponatremia, hypocalcemia), renal and hepatic disease.Recent evidence has indicated that both cerebral vascularaccidents and periventricular 42 white matter disease are related todepressive symptoms in the elderly 44,45 .Table 29.1Laboratory testCompleteblood countElectrolytesB 12 /FolateThyroid panelLiver enzymesCalcium/phosphorusGuiaic stoolUrinalysisConsider additional testincluding:ElectrocardiogramElectroencephalogramUrine drug screenLaboratory work-up in the depressed elderly patientHuman immunedeficiency virus(HIV)Brain computedtomographyBrain magneticresonance imagingproper treatment, and estimates of the number of patients withreversible conditions presenting as dementia have been as high as15% 17 . The work-up of medical conditions that present withdepressive symptoms in the elderly includes a personal history ofmedical illness, mental status examination and laboratory tests 46 .The physical examination and laboratory diagnosis is crucial inthe diagnosis of medical disorders. The typical laboratoryscreening for elderly patients with depressive symptoms isoutlined in Table 29.1. Clearly, the medical history and physicalexamination would influence the laboratory testing that wasactually done. The neurologic examination should be particularlythorough and include an examination of both subtle (e.g. frontalreflex signs) and prominent (e.g. reflex changes) signs ofneurologic dysfunction.MEDICATION HISTORYUnderlying conditionInfectious diseaseEncephalitisMeningitisSub-acute bacterial endocarditisAnemiaHypokalemiaHyponatremiaDiabetesUremiaPernicious anemiaHypo/hyperthyroidismHepatitisLiver cancerHyperparathyroidismColon diseaseInfectionRenal diseaseParticularly patients who complain of fatigue,edema, shortness of breath or who are beingconsidered for antidepressant therapyWhen delirium may be a concern or to screenfor a mass lesionFor lead (exposure to paint), mercury (textilemanufacturing), organophosphates andarsenic (insecticides). Also drugs of abuse(e.g. opiates, marijuana, etc.)Exposure to potentially contaminated bloodproducts (surgery, drug use) or a history ofpromiscuity or homosexualityNeoplasia, strokeParticularly to view the posterior brain stemMedication, including the antihypertensive medications such aspropranolol and centrally acting a-methyldopa and reserpine, hasbeen shown to cause depressive symptoms. Drugs such as alcoholare also frequent causes of depression in the elderly, as are thebarbiturates that are used as sedatives. Patients at risk should bescreened for heavy metals, including lead, arsenic and theorganophosphates.MEDICAL WORK-UPMedical conditions also present with depressive symptoms in theelderly. Many of these medical conditions are reversible withSUMMARYDepressive symptoms are common in the elderly, whereas thesyndrome of a major depressive episode is relatively rare 6,45 .