Altered Hippocampal Morphology in Unmedicated Patients with Major Depressive Illness

Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA 90095, USA.
ASN Neuro (Impact Factor: 4.02). 10/2009; 1(4). DOI: 10.1042/AN20090026
Source: PubMed


Despite converging evidence that major depressive illness is associated with both memory impairment and hippocampal pathology, findings vary widely across studies and it is not known whether these changes are regionally specific. In the present study we acquired brain MRIs (magnetic resonance images) from 31 unmedicated patients with MDD (major depressive disorder; mean age 39.2+/-11.9 years; 77% female) and 31 demographically comparable controls. Three-dimensional parametric mesh models were created to examine localized alterations of hippocampal morphology. Although global volumes did not differ between groups, statistical mapping results revealed that in MDD patients, more severe depressive symptoms were associated with greater left hippocampal atrophy, particularly in CA1 (cornu ammonis 1) subfields and the subiculum. However, previous treatment with atypical antipsychotics was associated with a trend towards larger left hippocampal volume. Our findings suggest effects of illness severity on hippocampal size, as well as a possible effect of past history of atypical antipsychotic treatment, which may reflect prolonged neuroprotective effects. This possibility awaits confirmation in longitudinal studies.

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Available from: Paolo Brambilla
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    • "Indeed, reduced BDNF expression has been observed in the hippocampus and prefrontal cortex of MDD and BD patients (6–8), coinciding with reduced volume of these structures (9–13), impaired spatial memory (14,15), and executive function (16,17), respectively. Interestingly, overexpression and underexpression of BDNF in different parts of the brain of mice impaired their learning and memory and precipitated depression-like behavior (18–20). "
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