In older adult patients with depression, both early- and late-onset conditions “have strikes against them,” because early-onset patients have longer and greater numbers of episodes, whereas late-onset patients may have several acquired biological factors that affect the brain directly, or there may be psychosocial factors that might “be less amenable to change,” he said.
Recently, a systematic review of studies of older and middle-aged adults with depressive conditions showed that an earlier age of onset and a larger number of depressive episodes were associated with a worse prognosis. But the presence of medical comorbidities explained most of the differences in prognosis and response to treatment. The review did not distinguish among the subtypes of depression (Am. J. Psychiatry 2005;162:1588–601).
Right now, evidence is too sparse to recommend specific medications or types of psychotherapy based on the older depressed patient's physical comorbidity.
In reviewing studies of about 700 primary care patients at the University of Rochester, Dr. Lyness and his colleagues have found that some physical illnesses–low vision, central nervous system diseases, diabetes, and hypothyroidism–appear to have independent associations with depression.
It may be best to reserve treatments for patients with troublesome depressive symptoms. DR. LYNESS