Abstract
Psychiatric disorders such as depression are common conditions in older adults. Depression presents similarly to younger adults, but with more psychotic symptoms and apathy. Research has suggested that genetics play a less important role in the etiology of depression in the elderly, but that other biological factors may be more significant. Vascular pathology in particular is thought to be especially important. White-matter hyperintensities are found in the frontal lobes and basal ganglia in greater numbers in older adults with depression, with damage to the frontal–subcortical circuits thought to be particularly important. It is associated with treatment resistance. Prognosis is poor if depression is not detected and treated adequately and this may lead to a higher risk of dementia and death. However, treatment with selective serotonin reuptake inhibitors and other antidepressants, plus psychological therapies, are effective in the older depressed patient and reduce morbidity and mortality.