Imaging and affective disorder in the elderly.

Changes in brain structure have been demonstrated in elderly patients suffering affective disorder. Enlarged ventricles are associated with cognitive impairment and higher mortality. Depressed subjects also may show a greater degree of cortical atrophy and subcortical white matter, and basal ganglia lesions seem to be commoner than in age-matched controls. The abnormalities demonstrated are not as severe as those found in degenerative dementias such as Alzheimer's disease, and at present there is no evidence to suggest they are progressive. There is a convincing association with vascular disease, although further neuropathologic correlates are needed. Functional imaging methods are just beginning to be applied to elderly populations and, in affective disorder, findings are similar to those in younger patient groups. The results from different groups vary due to technologic differences and the clinical heterogeneity of the patients studied. Depression, however, may be accompanied by decreased and mania by increased cerebral blood flow or metabolism. Evidence also appears to be mounting of a state-dependent frontostriatal dysfunction in depression. Challenges for the future include replicating such results using larger diagnostically homogeneous patient groups and differentiating the findings from those in other disorders such as schizophrenia and basal ganglia disorders.