Mohammed T. Abou-Saleh

410 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYTable 74.2Diagnostic features distinguishing depression from dementiaTable 74.3Medications reportedly associated with depressionDepressionDepressive symptomsSubacute onsetHistory of depression moreAphasia, apraxia, agnosia absentOrientation intactConcentration impairedPatient emphasis on memorycomplaintPatient gives up on testingAdapted from Wells 56 .DementiaEuthymiaInsidious onsetHistory of depression lessAphasia, apraxia, agnosia presentOrientation impairedRecent memory impairedPatient minimizes memory complaintPatient makes effort on testingDepression in late life may be masked not only by somaticcomplaints but also by cognitive difficulties, reflecting yet anotheratypical form of depression observed in older adults. Difficulty inconcentrating or memory loss may result in the clinical picture of‘‘depressive pseudodementia’’ 56 .Thisdementia syndrome of depressionrepresents a reversible syndrome of dementia that may beclinically indistinguishable from irreversible dementias (Table74.2) 57,58 . These individuals frequently make little effort to cooperatewith mental status examination and the patient answers ‘‘Don’tknow’’ to many questions. However, notable losses of both recentand remote memory are observed, and these patients may showmarked variability on the performance of tasks of similar difficulty.In some cases, depression may be diagnosed retrospectively after afavorable response to a trial of antidepressant medication 19 .Furthercomplicating the issue, in about 20% of cases of true dementia amajor depression may coexist 59 . In these cases, both mood andfunction may improve when treated with an antidepressant therapy,but the basic cognitive impairment remains.Depression Secondary to a General Medical ConditionDepression may be intimately related to general medical diseaseor other ‘‘organic’’ influences. Of course, the relationship betweensomatic symptoms in the medically ill elderly and complaints ofdepression may be complex; older individuals are presumablymore vulnerable to the stresses of poor health and disability thatinterfere with body image, self-esteem and autonomy. Comorbidityis the rule, rather than the exception, and linkedsignificantly to functional decline across multiple parameters withincreasing age. Co-morbidity of depression with medical illness isassociated with poor physical, mental and social functioning, allof which compound the patient’s ability to enjoy the quality oflife. Not only may medical problems act as precipitators ofdepression, but many direct effects of medical conditions induce asecondary form of depression (Table 74.3) 9,10 . Medications,including anxiolytics, antihypertensives and neuroleptics, mayinduce a syndrome of depression. Polypharmacy and druginteraction may further serve to culminate in a depressive illness.The association between depression and general medical–surgicalproblems may be summarized as follows: (a) physical disease isassociated with narcissistic injury, loss of autonomy, pain and fearof impending death, frailty (to be discussed) and diminishedquality of life; (b) physical illness may directly (e.g. a cerebrovascularaccident) or indirectly (e.g. hypercalcemia) cause adepressive syndrome; or (c) medications used to treat medicaldiseases may themselves induce depression. These parameters aremore significantly affected than in an individual with depressionalone or general medical illness without depression 60 . Thus,among individuals with depression in the context of dementia,individuals who experience co-morbid depression and generalCardiovascular drugs Hormones Psychotropicsa-Methyldopa Conjugal estrogens AnalgesicsReserpine ACTH (corticotropin) Anti-parkinsonianPropranolol and glucocorticoids AntihistaminesGuanethidine Anabolic steroids BenzodiazepinesClonidineThiazide diureticsOther sedativehypnoticsDigitalisTypical neurolepticsAnti-inflammatory/Anticancer agents anti-infective agents OthersCycloserine Non-steroidal anti- Cocaine (withdrawal)inflammatory agents AmphetaminesEthambutol(withdrawal)DisulfiramL-dopaSulfonamides CimetidineBaclofenRanitidineMetoclopramideAdapted from Agency for Health Care Policy and Research 78 .medical illness are less active, with fewer social contacts thatexplain increased disability risk 45 . Physical immobility and socialisolation in turn increases disability over time, which furtherdecreases mobility and social interactions, placing the person atrisk for physical, psychological and social impairment 61,62 . Forsome individuals, the end result is a downward spiral in health,functioning and quality of life, a syndrome described bygeriatricians as ‘‘frailty and failure to thrive’’. This manifestationis characterized by weight loss, weakness, fatigue, inactivity,decreased food intake and depression. Physical signs that mayaccompany these symptoms include sarcopenia, balance and gaitabnormalities, deconditioning and decreased bone mass 63,64 .Failure to thrive specifies an end-stage of frailty that ischaracterized by unchecked weight loss, severe muscle wasting,apathetic depression and a host of physiologic abnormalities,including hypoalbuminemia, low creatinine, anemia, bicuspidulcers and untimely death 65 . Indeed, depression in the elderly isclosely related to the state of one’s physical health.Subsyndromal DepressionSubsyndromal depression is defined as depressive symptoms thatdo not qualify for a formal mood disorder using current clinicalcriteria. However, several studies have revealed that subthresholddepressive states can be associated with adverse clinical outcome.Additionally, subsyndromal depression may be a risk factor forsubsequent major depression 66 . Subthreshold depressive disordertends to be a heterogenous group of milder forms of depressionwith symptom patterns qualitatively distinct from more severedepressions such as major depression. According to the Berlinaging study, a subthreshold depression can be characterized intwo ways among the elderly 67 ; first, as a quantitatively minorvariant of depression or a depression-like state, with fewersymptoms or with less continuity; second, as a conditionqualitatively different from major depression, with fewer suicidalthoughts or feelings of guilt or worthlessness, while worries abouthealth and weariness of living occur with a similar frequency.CLINICAL FEATURES AND PROGNOSTICFACTORSThe paucity of controlled studies in the diagnosis and phenomenologyof depression and dysthymia in older adults restricts