Depression duration but not age predicts hippocampal volume loss in medically healthy women with recurrent major depression

This study takes advantage of continuing advances in the precision of magne tic resonance imaging (MRI) to quantify hippocampal volumes in a series of human subjects with a history of depression compared with controls. We soug ht to test the hypothesis that both age and duration of past depression wou ld be inversely and independently correlated with hippocampal volume. A sam ple of 24 women ranging in age from 23 to 86 years with a history of recurr ent major depression, but no medical comorbidity, and 24 case-matched contr ols underwent MRI scanning. Subjects with a history of depression (post-dep ressed) had smaller hippocampal volumes bilaterally than controls. Post-dep ressives also had smaller amygdala core nuclei volumes, and these volumes c orrelated with hippocampal volumes. In addition, post-depressives scored lo wer in verbal memory, a neuropsychological measure of hippocampal function, suggesting that the volume loss was related to an aspect of cognitive func tioning. In contrast, there was no difference in overall brain size or gene ral intellectual performance. Contrary to our initial hypothesis, there was no significant correlation between hippocampal volume and age in either po st-depressive or control subjects, whereas there was a significant correlat ion with total lifetime duration of depression. This suggests that repeated stress during recurrent depressive episodes may result in cumulative hippo campal injury as reflected in volume loss.