Depression in Older Adults

Tracey Holsinger, M.D.
Fellow in Geriatric Psychiatry
Northwestern University Medical School

Depression is an important cause of suffering among older adults as well as a significant contributor to the morbidity and mortality caused by other illnesses. Depressive symptoms have been associated with increased risks of myocardial infarction and death(1) and mood changes have been found to herald cardiovascular events.(2) Rates of depression are higher among patients with diabetes(3) and arthritis.(4) Twenty-five to thirty percent of stroke patients are depressed at the time of initial interview. Of note, depression is more common with left sided infarcts and more common with more anterior infarcts. (5) The diagnosis of major depression is often overlooked and with it the chance to intervene in a treatable condition, frequently with good outcomes.

Estimates of the prevalence of depression vary according to the criteria used for diagnosis and the living situation of the survey population. Data from the Epidemiological Catchment Area (ECA) study of more than 18,000 adults conducted in five sites(6) found lifetime rates of depression of 2% of men and 3% of women over the age 65 while 15% of geriatric respondents had some current depressive symptoms. In a primary care geriatric clinic population, the prevalence has been estimated at 5%. In nursing homes, estimates have ranged from 15-25% at any given point with an incidence of 13% per year.(7, 8)

Appropriate diagnosis and treatment of depression can not only ease the suffering associated with the depression itself and eliminate the excess disability added by the condition but also lower the mortality of direct and indirect self destructive behavior. The highest suicide rates occur in men over 75 years old. (9) The general population suicide rate is 12.4 per 100,000 while among 80-84 year olds it is 26.5 per 100,000.7 Indirect self destructive behavior, such as not eating and medication noncompliance, is much more common than suicide, and has been associated with decreased survival. (10)

There is a tendency to view suicide as a reasonable alternative in elderly populations, but only 5-10% of the older adults who make attempts have a terminal illness while 95% have a psychiatric illness, usually major depression. Elderly white males without a spouse have the highest suicide risk.(11) More than 75% of the elderly who commit suicide saw their primary care provider in the month preceding their death. Generally they are having a first major depressive episode with moderately severe symptoms.7 The elderly are less likely than younger patients to make a suicidal gesture as an attempt to get help. Only 7% of unsuccessful suicide attempts are made by the elderly, and 75% of these had lethal intent.(9) Those who do survive an attempt remain a high risk group for future attempts.

There are many barriers to the diagnosis of this treatable illness. Many older adults consider depressive symptoms to be a "normal" part of aging and may not report their symptoms to a physician. Many physicians also attribute some depressive symptoms to old age or other physical infirmities. Some elderly patients with depression present with "failure to thrive" rather than specific complaints.(12) Often a mood disturbance is not reported by an elderly patient, or the mood disturbance may be less prominent than multiple somatic complaints. However, it is possible to diagnose depression in the setting of medical causes of depressive symptoms. (13)

Diagnosis of a major depressive episode as defined by the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, (DSM IV) (7) Dysthymic disorder is diagnosed when a chronically depressed mood (more days than not for at least two years) is present with two of the above mentioned symptoms. A helpful mnemonic for remembering the depressive symptoms is SAD FACES:

Sleep Appetite/Anhedonia Dysphoria

Fatigue Agitation/Anhedonia Concentration (decreased) Esteem (decreased) Suicidal

While laboratory tests can and should be used to rule out medical causes of depression, there are no laboratory tests that are useful in making the diagnosis of depression. As in younger patients the dexamethasone suppression test is often abnormal, but it is not specific enough to be relied upon for diagnosing depression.(11) Recommended laboratory studies to rule out other causes of mood disturbance include thyroid functions, levels of B12 and folate, and basic blood chemistries. Imaging studies are indicated only if there are history or physical exam findings suggesting a neurologic disorder that would alter the treatment plan.

There are a variety of safe and effective treatment options for depressed elders. Of the many antidepressants available, none have demonstrated efficacy superior to the others; however, the serotonin re-uptake inhibitors have been associated with fewer side effects and therefore may inspire more compliance. The various classes of antidepressants are characterized below with the most common side effects and the most worrisome side effects. When beginning a patient on an antidepressant it is important to stress that response may take up to 12-13 weeks to develop, much longer than the six weeks required for younger adults. (15) Approximately 60% of depressed older adults respond to antidepressants (15,16) leaving many patients with residual symptoms. Both individual and group psychotherapy can be helpful in addressing these issues and residual symptoms. The decision of when it is appropriate to discontinue effective antidepressant therapy is under current study. In patients who have an illness characterized by recurrent major depressive episodes, the continuation of therapy at the doses used to treat an acute episode significantly reduces the chances of recurrence.

Class	Most Common Side Effects	Most Dangerous Side Effects
Selective Serotonin Reuptake Inhibitors	nausea, vomiting, headache, sexual dysfxn	SIADH (low Na) serotonin syndrome induced mania
Tricyclic Antidepr.	constipation, sedation, dry mouth, weight gain	lethal overdose, cardiac arrythmia, induced mania, delirium, orthostatic hypotension
Monoamine Oxidase Inhibitors	orthostatic hypotension, weight gain, edema, sexual dysfxn, insomnia	hypertensive reaction, lethal overdose, induced mania
Venlafaxine	headache, somnolence, dry mouth, nervousness, nausea	incr. diastolic BP induced mania
Nefazodone	somnolence, dry mouth, nausea, headache	induced mania
Mirtazapine	somnolence, increased appetite, weight gain, dizziness, dry mouth	agranulocytosis, transaminase elevations, induced mania
Bupropion	headache, nausea, insomnia, agitation	seizures, induced mania

Trazodone is an antidepressant that few patients can tolerate in the doses necessary for antidepressant efficacy. Because tolerance does not develop and because trazodone has no anti-cholinergic side effects, it is a reasonable sleep aid. Patients should be warned about the commonly occurring orthostatic hypotension and the much less common priapism.

Electroconvulsive therapy remains a safe and effective therapy for depression in the elderly. Indications for ECT include a treatment refractory depression, a life threatening situation where rapid response is required (usually a patient who has stopped eating and drinking or is acutely suicidal), and patient preference. ECT is also the most effective treatment for psychotic depression. (17)

Most cases of geriatric depression are successfully treated by the primary care physician. Psychiatric referral is appropriate for psychotherapy, for the acutely ill patient who has suicidal ideation, or for the patient who has a depression with psychotic symptoms. A referral for psychiatric evaluation and treatment may be helpful in cases where the diagnosis is unclear or when antidepressant trials fail.