13,14 The research demonstrating the importance of depression as an antecedent of medical illness was conducted in populations of aging rather than aged individuals. Among the elderly, the most salient issues may not be related to the initial incidence of either depression or disabling disease,

but, instead, to how existing disorders affect each other. Evidence that established physical illness can affect the clinical course of depression comes, for example, from observations that depression may be more persistent among those patients with cardiac disease than several other Inhibitors,research,lifescience,medical chronic diseases,15 and that it may be more resistant to antidepressant treatment in frail elderly patients for whom disabling medical illnesses have led to protein-calorie selleck screening library malnutrition than among individuals who are more fit.16 Viewing the paths in the opposite direction, there is also evidence from multiple sources that depression can affect the clinical course of established Inhibitors,research,lifescience,medical medical illnesses by presenting barriers to convalescence and recovery, increasing disability, cognitive impairment, pain, and related Inhibitors,research,lifescience,medical symptoms.17 These findings can be summarized with the unifying hypothesis that depression amplifies the morbidity and disability associated with medical illnesses; they suggest that the recognition and treatment of depression in the presence of other medical illnesses can serve as a form of secondary prevention

that can decrease the impact of these conditions.18 Some recent studies have challenged the basic model of Stenstedt, Hopkinson, and Mendlewicz. Inhibitors,research,lifescience,medical Lyness and coworkers studied a sample of elderly patients hospitalized for depression and found comparable measures of physical illness in those with early- and late-onset disease.19 Although their findings appear inconsistent with earlier distinctions between early- and late-onset depressions, it is important to note that more than a generation elapsed Inhibitors,research,lifescience,medical between

these studies, and that the relative contribution of the path that extends from medical illness to depression versus that which extends from depression to medical illness may well vary over time as a result of cohort effects, increases in longevity resulting from changes in lifestyles and medical care, and advances in the treatment of both medical and mental illnesses. Another challenge to this model comes from studies of Rutecarpine patients with one specific type of comorbidity: major depression as it coexists with Alzheimer’s disease. Here depression is, in fact, associated with an excess of depression among first-degree relatives, suggesting that depression in Alzheimer’s disease occurs among those who are at increased genetic risk.14,20-23 These findings suggest that the mechanisms linking depression with other disorders may differ between conditions, and that specific studies of the associations between depression and commonly occurring comorbidities may be of value.