Background: Previous studies have shown that major depression is frequently accompanied by hypercortisolemia. There is some evidence suggesting that an increase in the glucocorticoid levels may make hippocampal cells more vulnerable to insults caused by hypoxia, hypoglycemia, or excitatory neurotransmitters. Using magnetic resonance imaging (MRI), the hippocampi of patients with major depression were measured and compared with values observed in control subjects.
Methods: Thirty-eight patients with primary unipolar major depression were recruited. Twenty control subjects were matched for age, gender, and years of education. The hippocampal volume was measured from coronal MRI scans in all of the subjects. Patients were also grouped and compared as responders and nonresponders to treatment with fluoxetine of 20 mg/day, for 8 weeks. Hamilton Depression Rating Scale (HDRS) was used to determine the severity of depression.
Results: No significant differences were observed between the hippocampal volumes of patients with major depression and control subjects; however, a significant correlation was observed between the left hippocampal volume of men and their HDRS baseline values. In addition, female responders had a statistically significant higher mean right hippocampal volume than nonresponders.
Conclusions: The results of our study indicate no reduction in the volume of the hippocampus in patients with major depression. Nonetheless, the results do suggest that the effects of disease severity, gender, and treatment response may influence hippocampal volume.