Late life depression (LLD) frequently presents with cognitive impairment, and growing evidence suggests that these disease processes are "linked" in multiple ways. For some individuals, LLD may be a recurrence of a long-standing depressive illness, while for others it may be the leading symptom of a developing neuropathological disorder. Overall, studies investigating the relationship between treatment of LLD and improvement in cognitive functioning have yielded mixed results. Research suggests that a subset of individuals with LLD and cognitive dysfunction will experience an improvement in cognitive function after antidepressant treatment, though a significant proportion will continue to exhibit cognitive impairment following resolution of their depressive symptoms. From a treatment standpoint, it is critical to ensure that an individual's depressive symptoms have been treated to remission, measured by a standardized rating scale such as the Geriatric Depression Scale (GDS). SSRI or SNRI monotherapy is often effective, and may be enhanced by employing an evidence-based psychotherapy such as Problem Solving Therapy (PST) or Interpersonal Therapy (IPT), modified to accommodate cognitive impairments that may be present. With respect to specific treatment of cognitive dysfunction, cognitive augmentation or training strategies can be helpful for some patients, and may be explored in combination with treatment of the primary depressive episode. While the introduction of a cholinesterase inhibitor (e.g. donepezil) may be considered, the potential benefit (modest improvement in cognition and functioning) must be weighed against an increased risk for worsening or recurrent depression. Finally, lifestyle factors-such as aerobic exercise, follow-up with a primary care physician for management of co-morbid medical illnesses, and regular participation in stimulating activities (such as through a senior center)-are important and should be included as part of the overall treatment plan.
Keywords: antidepressant; cognitive training; dementia; electroconvulsive therapy; emerging treatments; late-life depression; mild cognitive impairment; pharmacotherapy; psychotherapy; treatment.