Hippocampal amygdala volumes in geriatric depression

Background. The hippocampus, amygdala and related functional circuits have been implicated in the regulation of emotional expression and memory proces ses, which are affected in major depression. Several recent investigations have reported abnormalities in these structures in adult and elderly depres sives. Methods. Elderly DSM-III-R unipolar depressives (N = 40) and normal control s (N = 46) participated in a magnetic resonance imaging study (1.0T). Brain images were obtained in the coronal plane. Using established anatomical gu idelines for structure delineation, volumetric measurements of left and rig ht hippocampus and anterior hippocampus/amygdala complex were completed und er blinded conditions using a semi-automated computer mensuration system, w ith patients and controls in random order. Results. Medial temporal volumes did not significantly distinguish either e lderly depressed and age-similar normal control subjects, or late onset and early onset depressed patients (ANCOVA). Major overlap of measured volumes existed between patient and control groups. In depressives, hippocampal vo lumes significantly correlated with age, and cognitive and depression ratin gs, but not with number of prior depressive episodes or age-at-onset of fir st depression. Conclusions. Hippocampal volumes do not discriminate a typical clinical pop ulation of elderly depressed patients from age-similar normal control subje cts. If hippocampal dysfunction contributes to a diagnosis of syndromal dep ression in the elderly, such dysfunction does not appear to be regularly re flected in structural abnormalities captured by volumetric measurement as c onducted. On the other hand, relationships between hippocampal volumes and clinical phenomena in depressives, but not controls, suggest potentially me aningful interactions between hippocampal structure and the expression of m ajor depression in the elderly.