Evaluating the associations between medical illness and depression As discussed above, observed relationships between mental and physical health can depend upon the cohort studied, the setting, and the population from which study samples are drawn. Additional problems arise in studies designed to investigate the associations of depression with specific

LGK-974 cost disorders and to evaluate underlying mechanisms. These arise because medical illnesses can lead to depression through the additive Inhibitors,research,lifescience,medical or interacting effects of a number of mechanisms. Some are general and are associated with factors such as the experience of disability, Inhibitors,research,lifescience,medical pain, stress, loss, or impaired self-esteem as a result of medical illness. Other more specific mechanisms may involve disease-related structural abnormalities in brain, or physiological abnormalities that affect the brain or the periphery. Any observed associations of depression with measures or correlates of physical illness could reflect general as well as specific mechanisms. Therefore, research must always include some

type of control for these nonspecific Inhibitors,research,lifescience,medical effects of disease. Another complication occurs in case of concomitant multiple disorders. Disabling chronic illnesses accumulate with aging such that middle-aged and “young-old” individuals often suffer from a single disorder,

but the “old-old,” most often, suffer from many. Investigations into the mechanism of association between mental and specific diseases or physiological Inhibitors,research,lifescience,medical abnormalities in homogeneous populations of younger individuals are less likely to be obscured by the presence of Inhibitors,research,lifescience,medical multiple, potentially interacting abnormalities, but they may miss mechanisms that arise specifically out of such interactions. Moreover, the problems associated with choosing control conditions are, perhaps, greatest in the presence of multiple disorders. In probing mechanisms, the salient questions are not whether specific disorders Mephenoxalone or abnormalities are associated with depression, but whether the associations remain significant after controlling for general mechanisms. One strategy may involve use of summary measures of comorbidity or illness burden that rely upon clinical judgments or information available from medical records. However, available instruments differ in the dimensions of illness considered, and there is no consensus as to what should be measured in rating illness severity. An alternative approach may be to use disability as a control measure.