Diederichs Chad, DeMayo Marilena M, Cole Jaeden, Yatham Lakshmi N, Harris Ashley D, McGirr Alexander
Department of Psychiatry, University of Calgary, Calgary, AB, Canada.
Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
Front Psychiatry. 2021 May 11;12:665402. doi: 10.3389/fpsyt.2021.665402. eCollection 2021.
Magnetic resonance spectroscopy (MRS) has been used to identify gamma-aminobutyric acid (GABA) alterations in mood disorders, particularly in the medial prefrontal cortex (mPFC) where decreased concentrations have been associated with anhedonia. In major depressive disorder (MDD), prior work suggests that repetitive transcranial magnetic stimulation (rTMS) increases mPFC GABA concentrations proportional to antidepressant response. To our knowledge, this has not been examined in acute bipolar depression. As part of a multicentre 4-week randomized, double-blind, sham-controlled trial using intermittent theta-burst stimulation (iTBS) of the left dorsolateral prefrontal cortex (DLPFC) in individuals with acute bipolar depression, we quantified mPFC GABA and Glx (glutamate+glutamine) concentrations using a 3T MRS scan at baseline and after the intervention. Depressive symptoms were measured using the Montgomery-Asberg Depression Rating Scale (MADRS) and the Hamilton Depression Rating Scale-17 (HRDS-17), and anhedonia was measured using the Snaith-Hamilton Pleasure Scale (SHAPS). The trial was terminated for futility and magnetic resonance spectroscopy data was acquired for 18 participants. At baseline, there were no associations between GABA or Glx concentrations and anhedonia, however GABA was negative correlated with depressive symptom severity on the HRDS-17. Compared to the sham-iTBS group, participants receiving active-iTBS had a significant increase in mPFC GABA concentrations. This was unrelated to antidepressant outcomes or improvements in anhedonia. Our data suggests that iTBS targeting the DLPFC is associated with physiological changes in the mPFC. In acute bipolar depression, our preliminary data suggests that mPFC GABA is dissociated from antidepressant iTBS treatment outcomes and anhedonia.
磁共振波谱（MRS）已被用于识别情绪障碍中γ-氨基丁酸（GABA）的改变，特别是在内侧前额叶皮质（mPFC），该区域浓度降低与快感缺失有关。在重度抑郁症（MDD）中，先前的研究表明，重复经颅磁刺激（rTMS）可使mPFC的GABA浓度升高，且与抗抑郁反应成比例。据我们所知，这在急性双相抑郁症中尚未得到研究。作为一项多中心、为期4周的随机、双盲、假对照试验的一部分，该试验对患有急性双相抑郁症的个体使用左背外侧前额叶皮质（DLPFC）的间歇性theta爆发刺激（iTBS），我们在基线和干预后使用3T MRS扫描对mPFC的GABA和Glx（谷氨酸+谷氨酰胺）浓度进行了量化。使用蒙哥马利-阿斯伯格抑郁评定量表（MADRS）和汉密尔顿抑郁评定量表-17（HRDS-17）测量抑郁症状，使用斯奈斯-汉密尔顿快感量表（SHAPS）测量快感缺失。该试验因无效而终止，共获得了18名参与者的磁共振波谱数据。在基线时，GABA或Glx浓度与快感缺失之间没有关联，然而GABA与HRDS-17上的抑郁症状严重程度呈负相关。与假iTBS组相比，接受活性iTBS的参与者mPFC的GABA浓度显著增加。这与抗抑郁结果或快感缺失的改善无关。我们的数据表明，针对DLPFC的iTBS与mPFC的生理变化有关。在急性双相抑郁症中，我们的初步数据表明，mPFC的GABA与抗抑郁iTBS治疗结果和快感缺失无关。
