Assessment and Treatment of Late-Life Depression
Comprehensive Assessment of LLD
The comprehensive assessment of patients with LLD can be carried out by health professionals in both mental health or primary care settings. In a multidisciplinary approach, psychiatrists and mental health professionals have collaborated with primary care providers using depression care managers with successful outcomes in managing depression in older adults [24,25]. Complete evaluation of a patient with suspected LLD begins with a history and physical and mental status examination. Other essential components of the evaluation include assessment of cognition, functional status, and suicide risk. Laboratory and neuroimaging studies may be necessary as well. Due to the comprehensive nature of this assessment, a multidisciplinary approach with collaboration between primary care, psychiatry, psychology, and ancillary services such as social work may be necessary. Multiple patient interactions may be required to complete a thorough evaluation.
History and Mental Status Examination
As with many other psychiatric illnesses, LLD is a clinical diagnosis. A careful history should be obtained initially utilizing open-ended questions. This should be followed by more directed questions as indicated to elicit the presence of depressive symptoms. The history should be obtained from the patient. A relevant collateral informant can be invaluable in the assessment, especially in cases where there is a comorbid neurocognitive disorder. However, the patient’s informed consent must be obtained prior to obtaining collateral information whenever possible. Psychosocial stressors that may have precipitated or may be perpetuating symptoms should be explored. Such stressors may include recent changes in living situation, loss of social support, recent deaths, or financial difficulties. Biological precipitants also need to be explored including presence of physical illness, depressogenic medications, and comorbid alcohol or other substance use. The patient’s past psychiatric history, psychiatric hospitalizations, and past medication trials should be ascertained. Any family history of depression, other psychiatric disorders, substance use disorders, and suicide attempts should be documented. A full mental status exam including cognitive assessment should be completed [21,26].
Cognitive Assessment
Cognitive impairment can be associated with LLD and may be due to the underlying depression or represent a comorbid neurocognitive disorder. Furthermore, the burden of medical illness as well as cerebrovascular and cardiovascular risk factors have been linked to executive dysfunction and reduced processing speed in individuals with LDD [27,28]. Distinguishing between these can be challenging; however, chronology of symptom onset is often helpful. Depression is more likely the etiology of cognitive impairment when depressive symptoms precede onset of cognitive deficits. This type of cognitive impairment is termed dementia syndrome of depression and may improve with treatment of depression [5]. Some patients may progress to develop major cognitive decline, and it remains unclear whether LLD represents a risk factor or prodrome to developing a major neurocognitive disorder [29]. On the other hand, if depression develops later in the course of cognitive decline, there may be an underlying neurocognitive disorder [17]. Up to 20% of individuals with major neurocognitive disorder due to Alzheimer’s disease also have major depression [11]. For these reasons, concomitant assessment of cognition is essential to the evaluation of the older adult presenting with depressive symptoms [30]. Cognitive domains that may be affected include learning and memory, language, attention, perceptual motor abilities, social cognition, and executive function [4]. Many of these domains can be assessed during the mental status examination, with brief cognitive screening tools, or with formal neuropsychological testing.
While there are numerous cognitive screening tools, some commonly used, brief tools include the Mini-Cog, the Folstein Mini-Mental State Exam (MMSE), and the Montreal Cognitive Assessment (MoCA). The Mini-Cog consists of a 3-item registration, delayed recall, and clock drawing test and has several advantages over other screening tools. It is a brief test (taking approximately 3 minutes to administer) with good sensitivity and specificity of 80% or greater. Compared with other cognitive screening tools, it is less influenced by level of education, language, or cultural background [31–33]. The MMSE is a longer screening tool consisting of 19 items and requires about 10 minutes to administer. Unlike the Mini-Cog, performance on the MMSE can be affected by level of education and cultural background. However, the MMSE can be administered serially to monitor changes in cognition over time [34,35]. The MoCA is a 10-minute cognitive screening tool first developed to detect mild cognitive impairment (MCI) [36]. The MoCA consists of 7 subscore sections covering visuospatial/executive function, naming, memory (delayed recall), attention, language, abstraction, and orientation. The total score is 30, and 1 point is added to the score if the testing subject has less than high school/12 years of education. The MoCA has demonstrated better sensitivity than the MMSE for the detection of MCI [36]. Elderly patients with depression often perform poorly on these cognitive screening tests due to apathy and poor effort.
Functional Assessment
The diagnosis of LLD requires that symptoms cause significant distress or interfere with functioning. A functional assessment is especially important in the evaluation of the older adult in that it allows clinicians to determine an individual’s ability to live independently and attend to daily needs. Basic activities of daily living (ADLs) include bathing, dressing, grooming, toileting, and self-transferring. Instrumental activities of daily living (IADLs) include more complex daily activities such as preparing meals, administering medications, driving, managing finances, and using simple electronics such as the telephone or remote control [26]. Impairment in IADLs is associated with increased depression severity. Conversely, the severity of depressive symptoms along with associated cognitive impairment predicts IADL impairment [37]. The Philadelphia Multilevel Assessment Instrument is a tool that can aid in the assessment of ADLs and IADLs and has been utilized in studies examining disability in depressed elderly patients [37,38]. Other available scales to quantify functional status include OARS Physical Activities of Daily Living, OARS Instrumental Activities of Daily Living Scale, and Direct Assessment of Functional Status Scale [26].
Suicide Assessment
Assessment for suicidality is an integral part of all psychiatric evaluations and is especially important in the evaluation of the depressed older adult. According to the Centers for Disease Control and Prevention, the suicide rate for individuals age 65 and older is 16.6 per 100,000, a figure that is comparable to that for individuals 18–64 years of age [39]. Non-Hispanic Caucasian males age 85 and older have the highest rate of completed suicide (56.5 per 100,000), underscoring the importance of a thorough suicide assessment [39]. Suicidality can range from passive thoughts of death and wishing that one were not alive, to active thoughts of self-harm with plan and intent. A Canadian study found 2% of community-dwelling adults age 55 and older had suicidal thoughts over a 12-month period and, of these, 28% had major depression [40]. A suicide assessment begins with inquiring about the presence of suicidal thoughts, plans, and intent. The 3 most frequently used methods of completed suicide in the elderly are firearms (28%), hanging (24%) and poisoning (21%) [41]. Access to weapons or other lethal means of self-harm such has hoarding of medications should be ascertained.
A complete suicide assessment requires attention to suicide risk factors, protective factors, and warning signs of impending suicide. Risk factors for suicide in the older adult include mood disorders, chronic medical illnesses and associated functional impairment, chronic pain, and psychosocial factors such as social isolation [42]. Mood disorders are present in 54% to 87% of cases of completed suicide, with major depression being the most common [42]. Chronic medical illness and pain can result in functional impairment leading to feelings of excessive guilt or being a burden to loved ones. Protective factors such as social connectedness, spirituality, religious beliefs, and cultural attitudes against suicide may serve as buffers against these risk factors [43]. Warning signs of impending suicide may indicate preparations for suicide and include feelings of hopelessness or lack of purpose, feeling trapped, talking about death, threatening suicide, agitation, social withdrawal, increased substance use and reckless behavior. Warning signs should prompt action to ensure the safety of the individual [44,45].
Physical Examination, Laboratory Studies, and Neuroimaging
Evaluation of LLD is not complete without a physical examination and ancillary studies to identify underlying medical conditions possibly contributing to or mimicking depressive symptoms. Routine laboratory studies include complete blood count, complete metabolic panel, thyroid studies, and urine drug screen. Signs and symptoms of underlying medical conditions may necessitate further laboratory studies [46]. Neuroimaging may reveal signs of cerebrovascular disease which can predispose, precipitate, or perpetuate depression in older adults [47].
Treatment
Treatment of LLD can take many forms and occur in various settings. Geriatric psychiatrists have expertise in the assessment and treatment of mental illness in the elderly. Workforce estimates for 2010 revealed 1 geriatric psychiatrist per 10,000 adults age 75 and over. This figure is estimated to decrease to 0.5 per 10,000 by the year 2030, underscoring the importance of increasing the knowledge base of clinicians across specialties who provide care to the depressed elderly [48]. The primary care setting is often the locus of care for depression in older adults; however, studies suggest that patients are often left untreated or undertreated [49]. Collaborative care models whereby mental health care is integrated into primary care have been shown to improve outcomes. The Prevention of Suicide in Primary Care Elderly: Collaborative Trial (PROSPECT) study found that use of care managers to assist primary care providers in identification of depression, offer algorithm-based treatment recommendations, monitor symptoms and medication side effects, and provide follow-up yielded improvement in outcomes. Patients in the intervention group were more likely to receive pharmacotherapy or psychotherapy, achieve remission, and showed greater decline in suicidal ideation [50]. Similar results were found in the Improving Mood-Promoting Access to Collaborative Treatment (IMPACT) study in which intervention patients treated under a collaborative care model showed lower depression severity, less functional impairment, and greater reduction in depressive symptoms [25].
Just as a collaborative care model can lead to improved outcomes, the overall strategy of treating depression must be multifaceted. The biopsychosocial model of disease first described in the 1970s emphasizes biological and psychosocial determinants of illness that must be addressed when treatment is considered [51]. This includes nonmodifiable biological factors such as age, gender, and genetic predisposition that may affect treatment options, as well as modifiable biological factors such as comorbid medical illness, medications, or substance use disorders. Psychological factors that can affect depressive symptoms include coping skills and defense mechanisms in the face of stressful life events. Social factors including the role of culture, environment, and family dynamics in disease presentation must be considered as well [52].
Pharmacologic Treatment of LLD
The primary pharmacologic treatment for depression is antidepressants. Treatment consists of 3 phases—acute, continuation, and maintenance. In the acute phase, the goal is remission of current symptoms and restoration of function. The continuation phase, extending up to 6 months after remission, aims to prevent relapse back into a depressive episode. Maintenance therapy is geared at preventing recurrence of future depressive episodes [53]. Studies have found a 50% risk of relapse after 1 episode of depression and 80% after 2 episodes. Up to 20% will develop chronic symptoms. For this reason, maintenance therapy is often necessary for recurrent depression [54].
