Late-life depression (major depressive disorder in adults 60 years of age or older) is often associated with coexisting medical illness or cognitive impairment. Either pharmacotherapy (with SSRIs as the initial choice) or psychotherapy may be used as first-line therapy.
Late-life depression is the occurrence of major depressive disorder in adults 60 years of age or older. Major depressive disorder occurs in up to 5% of community-dwelling older adults, and 8 to 16% of older adults have clinically significant depressive symptoms. Rates of major depressive disorder rise with increasing medical morbidity, with reported rates of 5 to 10% in primary care and as high as 37% after critical care hospitalizations.
•How do patients with late-onset depression compare to those with an initial diagnosis earlier in life?
Patients with late-life depression are heterogeneous in terms of clinical history and coexisting medical conditions. As compared with older adults reporting an initial depressive episode early in life, those with late-onset depression are more likely to have neurologic abnormalities, including deficits on neuropsychological tests and age-related changes on neuroimaging that are greater than normal; they are also at higher risk for subsequent dementia. Such observations informed the hypothesis that vascular disease may contribute to depression in some older adults. Low mood may be less common in older adults with depression than in younger adults with the disorder, whereas irritability, anxiety, and somatic symptoms may be more common. Psychosocial stressors such as the death of a loved one may trigger a depressive episode, although transient reactions to major losses can resemble depression.
Table 1. DSM-5 Diagnostic Criteria for Major Depressive Disorder.
•What is the recommended initial evaluation in elderly patients suspected of having depression?
Recommended laboratory tests include blood counts to test for anemia and measurement of the glucose level, as well as measurement of thyrotropin, since hypothyroidism can mimic depressive symptoms. Measurement of serum levels of vitamin B12 and folate is also commonly recommended, because the prevalence of vitamin B12 deficiency increases with age, and low levels of vitamin B12 and folate may contribute to depression. Cognitive screening (e.g., with the Mini-Mental State Examination) is warranted in persons reporting memory problems and may reveal deficits in visuospatial processing or memory even if the total score is in the normal range. Neuropsychological testing may help identify early dementia, but because acute depression negatively affects performance, testing should be postponed until depressive symptoms diminish.
Morning Report Questions
Q: What is considered the first line pharmacologic treatment for late-life depression?
A: Owing to their favorable adverse-event profiles and low cost, selective serotonin-reuptake inhibitors (SSRIs) are first-line treatments for late-life depression. In some randomized, controlled trials, but not others, SSRIs such as sertraline, fluoxetine, and paroxetine have been more effective than placebo in reducing depressive symptoms and increasing rates of remission of depression. Serotonin-norepinephrine reuptake inhibitors (SNRIs) are commonly used as second-line agents when remission is not obtained with SSRIs. In small studies, venlafaxine did not show greater efficacy than placebo, but a larger, placebo-controlled trial of duloxetine showed significant improvements in late-life depression (response rate, 37% vs. 19%; remission rate, 27% vs. 15%). As observed in trials involving younger adults, randomized trials involving older adults have not shown significant differences between the benefits of SSRIs and those of SNRIs, although adverse effects may be more frequent with SNRIs. Tricyclic antidepressants have efficacy similar to that of SSRIs in the treatment of late-life depression but are less commonly used owing to their greater side effects.
Table 3. Antidepressants Commonly Used to Treat Late-Life Depression.
Q: Is there a role for brain stimulation in treating late-life depression?
A: Electroconvulsive therapy (ECT) is the most effective treatment for severely depressed patients, including elderly patients. Although antidepressant medication is first-line therapy, ECT should be considered in patients if they are suicidal, have not had a response to antidepressant pharmacotherapy, have a deteriorating physical condition, or have depression-related disability that threatens their ability to live independently. Available data from open-label trials, typically involving persons who had not had a response to antidepressants, suggest remission rates of 70 to 90% with ECT, although remission rates in community samples may be lower (30 to 50%). Common side effects include postictal confusion with both anterograde and retrograde amnesia; current administration techniques, such as unilateral electrode placement with a brief pulse, substantially reduce this risk, and cognitive symptoms typically resolve after the completion of ECT. Persons with cardiovascular or neurologic disease are at increased risk for ECT-related memory problems. Transcranial magnetic stimulation is a newer treatment for depression that uses a focal electromagnetic field generated by a coil held over the scalp, most commonly positioned over the left prefrontal cortex. Sessions are scheduled five times a week over a period of 4 to 6 weeks. This treatment does not require anesthesia and does not have cognitive side effects. However, a meta-analysis of six trials comparing transcranial magnetic stimulation with ECT showed that ECT has higher remission rates. Although a large multisite trial did not show that age was a significant predictor of response, other studies have suggested that depressed older adults may not have as robust a response as younger adults.