Cognitive Deficits in Late-Life Depression: From Symptoms and Assessment to Therapeutics

Cognitive symptoms and deficits are core features of late-life depression (LLD), with an estimated 20%-50% of affected individuals meeting diagnostic criteria for mild cognitive impairment (MCI). Cognitive deficits, especially executive dysfunction, have consistently been associated with poorer treatment outcomes among people with LLD. Furthermore, distinguishing depression with cognitive complaints or cognitive impairment from the early stages of Alzheimer's disease (AD) can be challenging. Cognitive concerns are often emphasized among those with LLD, although, paradoxically, their description of memory difficulty may include detailed recall of specific memory lapses. Conversely, people with AD often have limited insight into their progressive cognitive decline, minimizing and concealing their cognitive difficulties. Neuropsychological assessment is one of the most useful means of clarifying this differential diagnosis. A subcortical cognitive pattern is commonly observed among people with LLD, including psychomotor slowing, variable attention, and executive dysfunction, which can affect memory encoding and free recall. A broad range of therapeutic approaches have been applied to older adults experiencing LLD along with cognitive symptoms, MCI, or dementia. Most studies focus on treatments to address LLD or MCI, with relatively fewer examining treatments specifically at this intersection. Nonpharmacological strategies, including aerobic exercise, cognitive remediation, and neuromodulation, are highly recommended to improve both depression and cognition. Antidepressants may have benefits for elements of cognition among people with LLD, but they have less evidence for their efficacy for people with cognitive deficits and dementia. This review provides an updated conceptual and practical framework for clinicians evaluating and treating LLD.