Larger amygdala volumes in first depressive episode as compared to recurrent major depression and healthy control subjects.

BACKGROUND: The aim of our study was to test the hypothesis that amygdala volumes are reduced in patients with recurrent major depression compared with first episode patients. METHODS: Using structural magnetic resonance imaging, we compared 30 inpatients with first-episode depression and 27 inpatients with recurrent major depression (DSM-IV) with healthy volunteer subjects from the local community matched for age, gender, and handedness. RESULTS: Patients with first-episode depression showed enlarged amygdala volumes compared with patients with recurrent major depression and healthy control subjects. No significant differences were found between patients with recurrent depression and healthy control subjects. No significant correlations were found between amygdala volumes and age of onset, illness duration, or severity of depression. CONCLUSIONS: Larger amygdala volumes in patients with first-episode depression may result from higher amygdala metabolism and blood flow. Additionally, disease progression with stress-related excitotoxic processes during recurrent depressive episodes might result in decreased amygdala volumes. Prospective investigations to investigate amygdala changes during the course of depression are needed.