Depression in older adults is a persistent or recurrent disorder resulting from psychosocial stress or the physiological effects of disease. This psychological problem can lead to disability, cognitive impairment, exacerbation of medical problems, increased use of health-care services, increased suicide, and increased risk of falls (Brown and Roose, 2011; Eggermont et al., 2012). It complicates the treatment of other physiological problems. Unfortunately, depression is severely under-recognized and undertreated. This lack of identification and treatment can be traced to providers assuming that the signs and symptoms of depression are normal age changes and/or normal responses to life events or medical problems.

Older individuals do not present with the typical symptoms of depression, such as depressed mood or sadness. They may, however, respond to focused questions about whether or not they feel depressed. Thus, it is important to ask older individuals directly about depression using brief screening tools or even by just asking if they feel depressed. The signs and symptoms indicative of depression that are reported may be related to a physical illness and exacerbated or exaggerated by the depression. While it is sometimes a slow and difficult diagnostic process, it is critical to rule out medical problems (acute or chronic) prior to a definitive diagnosis of depression. Once identified, depression is often not treated due to concerns about drug side effects associated with antidepressants and polypharmacy and beliefs that psychotherapy and other nonpharmacological interventions will not be effective for older individuals. While side effect concerns are appropriate, it is important to appreciate that depression in older patients is treatable.

Sorting out the complex interrelationships between symptoms and signs of depression caused by physical illnesses and those caused primarily by an affective disorder or related psychiatric diagnosis is challenging for health-care providers. Recognition and appropriate management of depression are critical, however, to optimize the management of comorbidities, maintain function and quality of life, reduce the need for health-care resources, and prevent further morbidity and even mortality. This chapter addresses these issues from the perspective of the nonpsychiatrist, highlighting diagnostic techniques and initial management options. It should be recognized, however, that the management of some older adults will best be done by involving psychiatrists and psychologists and possibly an integrated care model approach (Ellison, Kyomen, and Harper, 2012).

The prevalence of major depression among older adults actually decreases with age, with this rate being approximately 5% to 10% of older person living in the community and presenting to primary care practices have diagnosable depression. Although an additional 2% of older individuals experience dysthymia (a chronic depressive disorder characterized by functional impairment and at least 2 years of depressive symptoms), this disorder also decreases with age. Major depression is found in 16% to 50% of older adults in nursing homes or acute care settings. The lower rate of major depression among community-living older individuals may be caused by selective mortality, institutionalization, missed diagnoses, and/or cohort effects (ie, older individuals tend to deny mental health problems such as depression). The prevalence of subsyndromal depression (ie, symptoms of depression that do not meet standard criteria for major depression), however, steadily increases with age and ranges from 10% to 25% among community-dwelling adults and increases to 50% among those in nursing homes or acute care settings (Meeks et al., 2011).

The implications of depression are substantial and include increased mortality and morbidity including increased incidence of metabolic syndrome, weight changes, and declines in function and impaired cognition. When depression is associated with other medical problems (eg, hip fracture or osteoarthritis), there is often an exacerbation of associated pain, poor compliance and motivation, and impaired recovery and function. Persons age 65 and over account for 25% of all suicides, and as many as 75% of older adults who commit suicide suffer from depression. Approximately 10% of community-dwelling older adults report passive thoughts about suicide, and 1% have had active suicidal ideation. Several factors are associated with suicide in the geriatric population (Table 7–1).

Lifelong bipolar affective disorder is not uncommon in the elderly persons; these disorders account for 10% to 25% of all geriatric patients with mood disorders and 5% of patients admitted to geropsychiatric inpatient units. The incidence of late-onset bipolar disease, however, decreases with age and presents differently than it does in younger individuals. The most important differences in presentation are that older adults tend to present with better psychosocial function, less severe psychopathology, and a higher frequency of neurological etiologies than younger individuals. Elderly patients with bipolar disorder are more likely to have a mixture of depression and marked irritability. Pressured speech that tends to go off on tangents is common, although the severity of thinking disturbance is less pronounced than in young adults and flight of ideas is less common. Hypersexuality and grandiosity may be present but also tend to be less prominent in older adults. Manic-like syndromes in late life are distinguished by a greater likelihood of confusion, often a reflection of an underlying cognitive disturbance, such as an incipient dementia.

Several biological, physical, psychological, and sociological factors predispose older persons to depression (Table 7–2). Aging changes in the central nervous system, such as changes in neurotransmitter concentrations (especially catecholaminergic neurotransmitters), may play a role in the development of geriatric depression. Vascular depression, commonly seen in about 30% of stroke survivors, is linked to white-matter hyperintensities, which are bright regions seen in the brain parenchyma on T2-weighted magnetic resonance imaging (MRI). Inflammatory markers such as interleukin 6 (IL-6) have likewise been associated with depression, as has vitamin D deficiency. Other physical problems such as impaired vision and chronic pain and mild cognitive impairment are similarly associated with depression. There are several medical diagnoses that increase the risk for depression in older adults. These include cardiovascular disease, cancer, Parkinson disease, stroke, lung disease, arthritis, loss of hearing, and dementia (Winter et al., 2011).

Many psychosocial factors increase the likely occurrence of depression in older adults. These factors include being unmarried, living alone, having limited or no social support, recent loss and prolonged bereavement, being a caregiver, and having a low socioeconomic status (Barua et al., 2010; Clark et al., 2013). Risk for depression is further increased if there is a family history of depression, current or past substance abuse, or the individual had a prior depressive episode or suicide attempt. Losses, whether real or perceived, are common in the geriatric population and can be a contributory factor to depression. Loss of job, income, and social supports (especially the death of family members and friends) increase with age and can result in social isolation and subsequent ongoing bereavement and frank depression. Loss of independence, which occurs with the loss of a driver’s license or acute declines in function, can further cause depression. Other psychosocial factors such as impaired spiritual well-being and a perceived sense of unmet needs have similarly been noted to contribute to depression.

Major depression typically is diagnosed by evidence of depressed mood and/or loss of interest or pleasure. There may also be an associated appetite change, particularly a loss of appetite, insomnia or hypersomnia, psychomotor agitation or retardation, loss of energy and fatigue, feelings of worthlessness, difficulties with concentration, and/or recurrent thoughts of death or suicide. These typical signs and symptoms are often not noted in older adults or assumed to be due to normal aging or other comorbidities. Older depressed patients are more likely to present with a preoccupation with somatic and cognitive symptoms and will less frequently report depressed mood and guilty preoccupations, have crying spells, sadness, fear, or feelings that their life has been a failure (Ellison, Kyomen, and Harper, 2012). They commonly report poor self-perception of health and complain repeatedly about constipation or urinary frequency. These individuals may not acknowledge sustained feelings of sadness. They will, however, report a persistent loss of pleasure and interest in previously enjoyable activities (anhedonia). Generally, older individuals do not exhibit the signs and symptoms of depressed mood that meet the criteria for a major depressive disorder.

Minor, or subsyndromal, depression is more common than major depression. It is defined as one or more periods of depressive symptoms that are identical to major depressive episodes in duration (2 weeks or longer) but that involve fewer symptoms and less impairment. An episode of subsyndromal depression involves either a sad/depressed mood or loss of interest/pleasure in nearly all activities.

The diagnosis of depression, whether major or minor, in older persons is complicated by the overlap of physical illness. Patients with serious medical illness may be preoccupied, for example, with thoughts about death or worthlessness because of concomitant disability. Older adults with depression also tend to have a higher rate of anxiety, nervousness, and irritability than their younger counterparts. They may engage in somatization and put themselves at risk for iatrogenic disease that occurs due to unnecessary tests and treatments. As noted earlier, rigorous steps must be taken to exclude any possible cause of their symptoms prior to concluding that depression is the primary diagnosis. However, this workup must consider the risks and benefits of any procedure or test for each individual.

Recognizing the signs and symptoms of depression and identifying depression disorders in older adults is complicated by many factors, including:

• The presence of common medical conditions (eg, Parkinson disease, congestive heart failure) that can result in the individual appearing depressed, even when depression is not present.
  
• Nonspecific physical symptoms (eg, fatigue, weakness, anorexia, diffuse pain) that are commonly associated with comorbid conditions.
  
• Specific physical symptoms, relating to every major organ system, can represent depression as well as physical illness in geriatric patients.
  
• Depression can exacerbate symptoms of coexisting physical illnesses such as exacerbation of memory changes or pain associated with arthritis.
  
• Pharmacologically induced depressive symptoms from substance use, particularly alcohol, and abuse or prescribed or over-the-counter medications.

The physical appearance of older patients suspected of being depressed should be interpreted cautiously. Normal age changes such as pale, thin, wrinkled skin; loss of teeth; kyphosis; and a wide-based slow gait, alone or in addition to the presence of diseases such as anemia or Parkinson disease, may make the older individual look depressed. Parkinson disease, which manifests by masked facies, bradykinesia, and stooped posture, can be misinterpreted as depression. Patients with sensory changes resulting in impaired vision and hearing may appear withdrawn and disinterested simply because they cannot see or hear you or others and, therefore, withdraw from social interactions. The psychomotor retardation of hypothyroidism may offer the physical appearance of depression. Systemic illnesses such as malignancy, dehydration, malnutrition, or chronic obstructive pulmonary disease can produce a depressed appearance with a flat affect or decreased energy. It is possible that the older individual will present with both medical problems and associated depression. In this scenario, it is critical that the medical management be optimized for each of the underlying problems and the depression treated so that quality of life and symptom management of the medical problems are optimized. Table 7–3 provides an overview of some common examples of somatic symptoms that may actually represent, or be exacerbated by, depression in older patients.

Insomnia

Older adults with mental health problems such as undiagnosed depression or anxiety may initially present with complaints of sleep disorders. Those with underlying shortness of breath, paroxysmal nocturnal dyspnea, anxiety and restlessness, and gastroesophageal reflux disease are likely to suffer from insomnia because these medical problems are exacerbated by a recumbent posture and may interfere with falling or staying asleep. Although it is one of the key symptoms in diagnosing different forms of depression, a variety of factors may underlie insomnia (Table 7–4). Insomnia can also be caused by the effects of (or withdrawal from) several medications or use of alcohol or late-night caffeine.

Older adults may complain of sleep problems caused by underlying physiological or psychological problems such as pain, anxiety, depression, shortness of breath, gastritis, or unrealistic sleep expectations (eg, belief in the need to sleep for a straight 8 hours). In addition, a number of specific sleep disorders are known to present more frequently in older individuals. Obstructive sleep apnea (OSA), which results in abnormal breathing, is the most common sleep-related problem. The development of OSA seems to be age dependent and male dominant. The incidence is also higher in individuals who are obese and have enlarged neck circumferences. The risks associated with untreated OSA include nighttime hypoxia with associated risks for cardiac arrhythmias and myocardial and cerebral infarction. Specific signs such as loud snoring, which are often elicited from the bed partner, should prompt the provider to refer the older individual to a sleep center for further workup. Once diagnosed, the treatment for OSA includes continuous positive airway pressure, dental appliances, and uvulopalatopharyngoplasty. Another common sleep disorder that can cause insomnia is restless leg syndrome (RLS). The incidence of RLS increases to 20% of those 80 years of age or older. Female gender, being retired, and unemployment were independent risk factors for RLS (Angelini et al., 2011). Patients with RLS have uncomfortable sensations in the lower extremities that they attempt to relieve by moving their legs during sleep or by rising and walking around. Managing RLS is challenging but can be achieved with medications.

Even without disease, aging is associated with changes in sleep patterns, such as daytime naps, early bedtime, increased time until onset of sleep, decreases in the absolute and relative amounts of the deeper stages of sleep, and increased periods of wakefulness, all of which contribute to the complaint of insomnia. Insomnia is a good example of how a primary symptom of depression must be evaluated to first determine that there is not an important and treatable underlying cause. It is important to avoid assuming or blaming the symptom on age or depression before a comprehensive medical workup has been completed.

Medical disorders that may imitate depressive symptoms are particularly important to consider in elderly patients because of the increased vulnerability of this population to physical illnesses. Hyperthyroidism, for example, may present with apathy and diminished energy that mimics depression.

Symptoms and signs of depression are associated with medical conditions in the geriatric population as evidenced by the following:

• Some diseases can result in the physical appearance of depression, even when depression is not present (eg, Parkinson disease).
  
• Many diseases can either directly cause depression or elicit a reaction of depression. The latter is especially true of conditions that cause or produce fear of chronic pain, disability, and dependence.
  
• Drugs used to treat medical conditions can cause symptoms and signs of depression.
  
• Changes in living environment, such as entering a nursing home or assisted living facility, can predispose to depression.

A wide variety of physical illnesses can present with or be accompanied by symptoms and signs of depression (Table 7–5). Any medical condition associated with systemic involvement and metabolic disturbances can have profound effects on mental function and affect. The most common among these are fever, dehydration, decreased cardiac output, electrolyte disturbances, and hypoxia. Hyponatremia (whether from a disease process or drugs) and hypercalcemia (associated with malignancy) may also cause older patients to appear depressed. Systemic diseases, especially malignancies and endocrine disorders such as diabetes, are often associated with symptoms of depression. Depression—accompanied by anorexia, weight loss, and back pain—is commonly present in patients with cancer of the pancreas. Among the endocrine disorders, thyroid and parathyroid conditions are most commonly accompanied by symptoms of depression. Most hypothyroid patients manifest psychomotor retardation, irritability, or depression. Hyperthyroidism may also present as withdrawal and depression in older patients—so-called apathetic thyrotoxicosis. Hyperparathyroidism with attendant hypercalcemia can simulate depression and is often manifest by apathy, fatigue, bone pain, and constipation. Other systemic physical conditions, such as infectious diseases, anemia, and nutritional deficiencies, can also have prominent manifestations of depression in the geriatric population.