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Updated: May 30, 2025

Individualized rTMS Treatment for Depression using an fMRI-Based Targeting Method
Published on: August 2, 2021
Low-dose ketamine improved brain network integrity among patients with treatment-resistant depression and suicidal
Tung-Ping Su1, Li-Kai Cheng2, Pei-Chi Tu3
1Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Psychiatry, Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Psychiatry, General Cheng Hsin Hospital, Taipei, Taiwan.
Background:
Ketamine is a dissociative drug used for the treatment of depression. However, the neurofunctional mechanism underlying the antidepressant effect of ketamine remains unknown. According to previous research, low-dose ketamine affects large-scale brain networks, including default-mode and salient networks.
Methods:
A total of 43 patients with treatment-resistant depression (TRD) and suicidal ideation (SI) were randomly assigned to receive a single infusion of either 0.5 mg/kg ketamine or 0.045 mg/kg midazolam. Depressive and suicidal symptoms were evaluated using the 17-item Hamilton Depression Rating Scale and the Columbia-Suicide Severity Rating Scale: Ideation Severity Subscale. Resting-state functional magnetic resonance imaging was performed at baseline and on day 3 after infusion. Graph theoretic metrics such as degree centrality and clustering coefficient were examined.
Results:
Relative to midazolam use, low-dose ketamine infusion reduced depressive (p = 0.001) and suicidal (p = 0.025) symptoms and improved the brain network integrity, including increased degree centrality and clustering coefficient in the angular gyrus and increased degree centrality in the right thalamus.
Discussion:
Neurofunctional changes in the thalamus and default-mode network (angular gyrus) may be associated with the antidepressant effect of ketamine on patients with TRD and SI.
Clinical Trials Registration:
UMIN Clinical Trials Registry (UMIN-CTR): Registration number: UMIN000033916.
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