Assessment and Treatment of Late-Life Depression

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.