Impact of Depression and Mental Illness on Outcomes of Medical Illness in Older Adults

Since the 1990s, observational studies have shown that depression and mental stress are common in older adults with medical illnesses and are associated with worse health and function outcomes. In one series of studies, symptoms of depression were observed in 33% of adults aged 470 years admitted to a general medical hospital service. 1,2 These symptoms were also associated with a 2- to 3-fold increased functional dependence at 1 and 3 months and 34% increased mortality 3 years postdischarge after adjusting for severity of illness and other covariates. Similarly, symptoms of depression were observed in 35% of adults hospitalized with congestive heart failure and were associated with a 2to 3-fold increased mortality and readmission 1 year postdischarge after controlling for adverse risk factors. 3 We also know that mental stress can directly precipitate adverse health events. In one study, feelings of frustration, tension, and sadness were associated with a 2-fold increase in myocardial ischemia within the subsequent hour in patients undergoing ambulatory ECG monitoring. 4 The causal link between depression and outcomes of medical illness is likely bidirectional and a classic “vicious” cycle: poor health precipitates symptoms of depression, and depression leads to worse health outcomes. Among patients diagnosed with mild Alzheimer’s disease, a decline in function preceded and was associated with the first episode of depression. 5 Similarly, among older adults admitted to a nursing home for rehabilitation after an acute hospital stay, 28% had depressive symptoms on admission but only one third of these had a documented diagnosis of depression, suggesting that the depression followed the acute illness and was mostly unrecognized by clinicians. 6 Halting this sequential cycle of declines in physical and mental health has the potential to improve health, quality of life, and daily function for medically ill older adults. However, in general, clinicians and researchers pay much more attention to addressing physical problems than they do mental problems. In one exception, a randomized study showed that enhanced care of depression with antidepressant medication and/or psychotherapy reduced pain and improved function in activities of daily living in older adults with osteoarthritis. 7 In another study, collaborative depression care delivered before the onset of cardiovascular disease halved the excess risk of myocardial infarction or stroke among older, depressed patients. 8 In this issue of Clinical Therapeutics, we bring together original investigations and reviews on contemporary issues in mental health for older adults with medical illnesses, including articles on depression and its pharmacologic and nonpharmacologic management, risks of pharmacologic treatment specific to older adults, and issues specific to long-term care and palliative care settings. Two studies report on the symptoms of depression in patients undergoing rehabilitation after an acute medical illness. First, Peterson et al 9 examine the relationship between exercise, symptoms of depression, and cardiac