Merck & Co., Inc.

The Merck Manual of Geriatrics logo

red line
click here to go to the Contents page of The Merck Manual of Geriatrics
click here to go to the title page of The Merck Manual of Geriatrics
click here to search The Merck Manual of Geriatrics
click here to go to the Index of The Merck Manual of Geriatrics
red line
Section 4. Psychiatric Disorders
this section includes
Chapter 32. Aging and Mental Health | Chapter 33. Depression | Chapter 34. Anxiety Disorders | Chapter 35. Somatoform Disorders | Chapter 36. Psychotic Disorders | Chapter 37. Substance Abuse and Dependence

Chapter 33. Depression

Contributor: Dan Blazer

A disorder characterized by feelings of sadness and despair and ranging in severity from mild to life threatening.

Depression is one of the most common psychiatric disorders among the elderly. The prevalence of clinically significant depressive symptoms ranges from 8 to 15% among community-dwelling elderly persons and is about 30% among the institutionalized elderly. Major depression occurs less often in later life than at younger ages and affects about 3% of elderly persons in the community, 11% in hospitals, and 12% in long-term care settings. The current cohort between ages 70 and 90 years has had fewer severe depressive episodes in adult life than earlier cohorts. The number of cases is expected to increase substantially over the next 20 to 30 years as younger cohorts, who have a higher prevalence of depression than the current elderly cohort, age.

Depression is one of the most common risk factors for suicide (see Table 33-1). The highest rates of suicide in the USA occur in persons >= 70. For white men, suicide is 45% more common among those aged 65 to 69 years, > 85% more common among those aged 70 to 74, and more than three and a half times more common among those >= 85 than among white men aged 15 to 19 years. Suicide rates do not increase with age among women. The elderly are less likely than younger patients to seek or respond to offers of help designed to prevent suicide. The elderly make fewer suicide gestures but more often succeed at suicide attempts. As many as 70% of elderly persons who completed suicide visited their primary care physician within the previous 4 weeks.

Etiology

The etiology of depression in the elderly, as in younger persons, is biopsychosocial.

Medical disorders may cause depression in the elderly (see Table 33-2) as may abuse of alcohol, some prescription drugs (especially some antihypertensives), cocaine, or other illicit drugs. Psychologic risk factors are similar across age groups and include guilt and negative thought patterns. Cognitive dysfunction is another major risk factor. Social risk factors (eg, loss of a spouse or partner, decreased social support) appear to cause depression more often in men than in women. Persons with lower incomes are at greater risk for depression.

Heredity plays less of a role in depression with first onset in late life than in that with first onset in midlife. However, persons who first experience depression in early or midlife and have a recurrence in late life are just as likely to report a family history as are persons who experience depression in midlife. Structural brain changes, seen on MRI and thought to be secondary to vascular insufficiency, are associated with depression in late life. Such cases are referred to as vascular depression.

Symptoms and Signs

Chronic and persistent dysphoria (restlessness, malaise) with a mildly depressed mood, common among the elderly, is not severe enough to warrant a diagnosis of depression. The clinical manifestations of depression in the elderly are listed in Table 33-3.

Episodes of brief depression, which are also common among the elderly, include moderately severe depressive symptoms that are consistent with the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria except for their duration (2 weeks). The symptoms may have no clear cause and may resolve spontaneously, and episodes may occur in increasingly rapid cycles.

Some elderly persons experience a brief period (usually lasting a few days) of severe depressive symptoms that usually can be explained by obvious difficulties in adjustment or by bereavement. Adjusting to a severe or ultimately fatal chronic illness and losing a spouse or partner are common causes of such symptoms. Affected persons recover with time or when the stressor resolves.

Dysthymic disorder, which may be chronic, persistent, and moderately severe, is defined by DSM-IV as a depressed mood with two or more additional symptoms (eg, sleep problems, decreased appetite, feelings of hopelessness, lethargy). Symptoms must persist for at least 2 years but are not severe enough to constitute a major depressive episode.

Major depression, with or without melancholia, includes a core symptom of dysphoric mood or loss of interest plus at least four of the following symptoms: sleep disturbance (usually decreased sleep), appetite disturbance, weight loss, psychomotor retardation, suicidal ideation, poor concentration, feelings of guilt, and loss of interest in usual activities (if not the core symptom). Melancholia is present if these symptoms are predominated by a lack of interest in the social environment, diurnal variation (ie, feeling significantly worse during one part of the day, usually the morning, compared with the remainder of the day), and psychomotor agitation or retardation.

Sometimes major depression is characterized predominantly by psychotic features, especially delusions of illness or guilt about past actions, thoughts, or events. (see page 329)

Psychotic depression is more prevalent in late life than in midlife. Generally, psychotic symptoms are similar among elderly and younger patients, although elderly patients usually have more of them and are less likely to experience self-deprecation and guilt.

Bipolar I disorder is characterized by one or more manic episodes, with or without episodes of depression. A manic episode is a distinct period (lasting >= 1 week) during which there is an abnormally and persistently elevated, expansive, or irritable mood. Manic episodes may occur for the first time in late life but most often recur from an earlier age. During a manic episode, a person may experience an inflated self-esteem, decreased need for sleep, increased talkativeness, a subjective sense that thoughts are racing, distractibility, psychomotor agitation, and involvement in activities that are perceived to be pleasurable but that can lead to adverse outcomes, such as unrestrained buying. Elderly persons are less likely to experience inflated self-esteem or grandiosity during an episode and are more likely to experience irritability and psychomotor agitation, thus making it somewhat difficult to distinguish a manic episode from agitated depression. A thorough history, including information from the patient and family, can assist in making this distinction. For example, if the elderly person has had previous episodes of depression associated with psychomotor retardation and, over a short period of time, enters an episode of acute agitation, decreased sleep, and increased talkativeness, a manic episode is likely even if the mood is dysphoric.

Some elderly persons may never experience an acute episode of mania but do have clear episodes of major depression. Between the episodes of depression, however, these persons are more elated or more irritable than usual. Such persons are diagnosed as having bipolar II disorder. The periods between episodes of depression may last for days, weeks, or even months. The symptoms, although uncharacteristic of the usual behavior of the elderly person, usually do not significantly interfere with function. Relatives and friends, however, may notice a problem with function.

Diagnosis

A thorough history and physical examination, including complete neurologic and mental status assessment, are necessary. A complete review of drug use (including illicit drugs) and alcohol use is also critical. Interaction with family members is helpful, and if the patient is demented or uncommunicative, obtaining a history from family members or other informants is essential. When the diagnosis is complicated by comorbid conditions or by poor communication with the patient, the physician should focus on the symptoms reported by family members and on change in symptoms over time.

The Geriatric Depression Scale (see Table 33-4) and the Hamilton Depression Rating Scale (see Table 33-5) are useful assessment instruments. However, they are screening devices and should not replace a thorough evaluation and interaction with the patient and family members.

Depressed patients should be asked directly about suicidal thoughts and intentions (eg, "Do you ever feel that life is not worth living? Have you thought of harming yourself?"). Asking about suicide does not increase the risk of suicide. Patients with suicidal thoughts should be asked about plans (eg, "Have you planned how you would do it?"). Those with suicidal plans should be hospitalized immediately.

Sometimes a definitive diagnosis cannot be made on the basis of history and examination alone. Such situations are common when demented patients stop eating or deteriorate in another way that suggests depression. A trial of treatment, usually with an antidepressant, is the best course for these patients.

Laboratory tests have an adjunctive role in the evaluation of depressed patients. However, thyroid function should be assessed for all new cases. A slightly low thyroxine level and an elevated thyroid-stimulating hormone level are common during a depressive episode. Most other tests should be ordered only when clinical findings suggest a concurrent disorder.

An ECG can provide a baseline if concerns arise about the effect of tricyclic antidepressants on cardiac function. Although not diagnostic, the dexamethasone suppression test may help predict prognosis. A positive test result (ie, a postdexamethasone cortisol level of > 5 µg/dL [140 nmol/L]) suggests that a relapse is likely if the level remains high, even when symptoms improve. Polysomnography, when available, can help identify melancholia; decreased sleep time with shortened rapid eye movement latency supports the diagnosis.

The differential diagnosis of major depression includes many medical and psychiatric disorders that may manifest as depression in later life (see Table 33-6).

Prognosis and Treatment

Patients with dysphoria rarely benefit from traditional modes of therapy. The outcome of major depression in late life, if uncomplicated, follows the "rule of thirds." One third of elderly patients get better and stay better, one third get better but relapse, and one third do not improve or improve only marginally. With time, however, most elderly patients who experience major depression in late life recover. Recovery, however, may take months. The prognosis is worse when depression is complicated by an underlying dysthymic disorder, by a medical disorder, or by cognitive impairment.

The key to the management of depression, especially major depression, in the elderly is early identification and intervention. All caregivers must be alert to the possibility of depression, especially when illness or loss of a loved one occurs. Family members, in particular, must be alert for subtle changes in personality, especially lack of enthusiasm and spontaneity, loss of sense of humor, and new forgetfulness. Loss of interest in sex may be apparent only to a spouse or other sexual partner. Nurses must be alert to loss of appetite, new sleep disturbances, and other signs and symptoms of depression. During treatment, family members and professional caregivers must be trained to monitor for adverse effects of drugs. They must also be alert to warning signs that the depression is worsening or that the patient is considering suicide.

Psychotherapy: Elderly patients with mild, recently established depression may respond to psychotherapy alone and may not need pharmacotherapy. Psychotherapy is often effective in treating depression without significant melancholic symptoms. When combined with antidepressants, it may benefit patients with severe depression. Behavioral and cognitive therapies are considered more effective than nondirected or analytically oriented therapies. Behavioral and cognitive therapies may help reintegrate the patient into a social environment after severe depression and may help prevent relapses, especially for episodic depression. Psychotherapy may be conducted by a psychiatrist, clinical psychologist, or mental health social worker, or it may require an interdisciplinary team.

Pharmacotherapy: Treatment of severe depression with melancholic features is primarily pharmacologic. Choosing a drug depends primarily on which one produces the fewest adverse effects. Although tricyclic antidepressants (eg, nortriptyline, desipramine, amitriptyline) are used often, elderly patients have difficulty tolerating the anticholinergic effects (especially those of amitriptyline) and the postural hypotension these drugs are likely to induce. Monoamine oxidase inhibitors are used less often because they have significant adverse effects and because they are not more effective than other drugs.

Therefore, the drugs of choice are the selective serotonin reuptake inhibitors (SSRIs [eg, fluoxetine, nefazodone, sertraline, paroxetine]), which have relatively few adverse cardiovascular and anticholinergic effects. However, agitation, a common adverse effect with some of these drugs (eg, fluoxetine), can be especially troublesome for elderly depressed patients. Sexual dysfunction is a problem for some persons who take SSRIs. Also, SSRIs can cause akinesthesia and other movement disorders.

Usual starting doses in otherwise healthy elderly patients are typically one half the usual adult doses: eg, fluoxetine 10 mg po daily, nefazodone 100 mg po bid, sertraline 25 mg po daily, or paroxetine 10 mg po daily. A typical starting dose for the tricyclic antidepressant nortriptyline is 10 to 25 mg po at night with gradual increases. Doses should be titrated upward slowly (eg, weekly) and not every 3 to 5 days as for younger adults.

Adjuncts may augment the response to antidepressants. For example, low-dose lithium may augment the effect of tricyclic antidepressants and SSRIs, and carbamazepine may reduce a patient's tendency to cycle in and out of depressive episodes. Methylphenidate has been used independently and as an adjunct to antidepressants, especially for patients in long-term care facilities. Its use may be advantageous for patients who have stopped eating because, if the drug works, it works quickly and also independently stimulates appetite. Methylphenidate may activate the depressed patient, is relatively safe, and rarely leads to dependence.

An acute manic episode may be treated with a mood stabilizer coupled with hospitalization to reduce the likelihood of behavior that can harm the patient or others; lithium carbonate, usually 300 to 600 mg/day, is the treatment of choice. Serum levels for effective therapy in the elderly are usually 0.4 to 0.8 mEq/L; higher levels are often associated with agitation and confusion. Given the toxicity of lithium, many clinicians elect to treat with valproic acid, at an initial dose of 10 to 15 mg/kg/day in 1 to 3 divided doses. Acute symptoms may require that the mood stabilizer be augmented with an antipsychotic drug (eg, olanzapine 2.5 mg daily, haloperidol 0.25 to 0.5 mg daily to bid). In such elderly patients, the doses of both the mood stabilizer and the antipsychotic drug must be increased significantly.

Electroconvulsive therapy (ECT): ECT is used for severely depressed patients, especially those who have previously responded to ECT, those who demonstrate significant psychotic symptoms or self-destructive behavior, and those who do not tolerate or respond to antidepressants. ECT is safest with multiple-channel monitoring (electroencephalography [EEG], ECG, blood pressure, pulse, and respiratory function); it should be administered by a psychiatrist under the supervision of an anesthetist or anesthesiologist. After rehydration, ECT is the treatment of choice for patients with malnutrition and dehydration due to severe depression.

ECT induces improvement in 80% of elderly patients who did not respond to antidepressants--the same rate as for younger patients. Maintenance ECT on an outpatient basis significantly reduces the likelihood of relapse for patients who responded to ECT. If maintenance ECT is impossible, then the risk of relapse can be reduced by the use of antidepressants, even if the patient did not respond to them initially.

Patients who undergo ECT experience acute amnesia, which is often distressing. Some memory loss can persist after ECT, but the nature and extent of this problem have not been determined.

Treatment of Medically Ill and Hospitalized Patients

Some patients respond to an acute or chronic medical disorder by developing a psychiatric disorder (eg, adjustment disorder with depressed mood). Support and psychotherapy (eg, formal intervention with the patient and family members) are often helpful. Small doses of SSRIs (eg, trazodone, 25 mg at night) can help, especially when sleep problems are present. For patients who are dying, similar measures can be used; however, not every dying patient needs psychotherapy or antidepressants. (see page 120)

Pharmacotherapy for major depression in patients with other medical disorders requires special attention. Tricyclic antidepressants and SSRIs (although SSRIs are of less concern) can cause adverse cardiovascular effects in patients with heart disease or unstable blood pressure (eg, a tendency toward orthostatic hypotension). Both classes of drugs are reasonably safe when used properly in patients without serious heart disease.

With longer hospitalization, the inability to respond to rehabilitative efforts and a patient's and family members' fears of chronic invalidism become proportionately greater. Hospitalized patients with depression often view themselves as hopeless; their hopelessness spreads to the staff members, who may pay less attention to them. Modifying the patient's environment may help (eg, involving the patient in group activities), but the depression itself also needs to be treated, usually with pharmacotherapy.

Copyright © 2009-2010 Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Whitehouse Station, N.J., U.S.A.  Privacy  Terms of Use  Sitemap