Longitudinal volume changes in nuclei of the amygdala following depression treatments and their relationship to anxiety improvement

Summary

Yuzuki Ishikawa, Naoya Oishi, Taro Suwa, Toshiya Murai, and their colleagues at Kyoto University analyzed structural MRI images of 155 patients with depression and 147 healthy participants collected at Kyoto University, Keio University, the National Center of Neurology and Psychiatry, and the Jikei University School of Medicine. They segmented the amygdala, a brain structure that has been reported to have abnormal structure and function in depression, into subdivisions based on previous anatomical findings, and examined longitudinal changes in the volume of each subdivision. They found that the right amygdala volume of patients with depression before treatment was smaller than that of the healthy participants. They examined longitudinal volume changes after four depression treatments including medication, cognitive behavioral therapy, electroconvulsive therapy (ECT), and transcranial magnetic stimulation, and demonstrated that only ECT-treated patients showed the post-treatment volume increase. The volume showed a slight decrease during the follow-up period, but was still larger at 6-months follow-up than that at pre-treatment. They also found that the pre-treatment volume of the right basomedial amygdala and the long-term volume change in the right basolateral amygdala were associated with improvement of anxiety symptoms in patients with depression, respectively. These results suggest that structural changes in the amygdala subdivisions observed after ECT, that is highly effective for depression, are associated with symptom improvement. The current findings are expected to contribute to the elucidation of the amygdala’s role in the mechanism of action of depression treatment and the development of new treatments.

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