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Arch Gen Psychiatry:创伤后应激障碍或和杏仁核体积变化相关

来源:生物谷 2012-11-06 23:33

2012年11月6日 讯 /生物谷BIOON/ --近日,来自杜克大学和杜伦VA医学中心的研究人员研究发现,被诊断为创伤后应激障碍(PTSD)的退伍军人,其大脑调节恐惧和焦虑效应的区域容量明显比正常人小,相关研究成果刊登于国际杂志Archives of General Psychiatry上。

早在20年前,研究者就发现了和PTSD相关的海马体的容量明显发生了改变,但是杏仁核又和PTSD明显相关,通过对动物进行研究,科学家确定杏仁核可以调节机体的恐惧、压力和焦虑表现,但是其对于人类行为的影响却不得而知。

这项研究中,研究者招募了200名2001年9月11后在阿富汗和伊朗战争中服役的军人,其中有一半军人诊断出PTSD障碍,而另外一般参与者也存在不同程度的外伤,但并未发展成为PTSD障碍。研究者通过MRI扫描来测定这些参与者的大脑杏仁核和海马体的容量。

研究者发现,PTSD的参与者其大脑左右两侧的杏仁核容量明显减小了,此前研究也揭示了PTSD患者的左侧海马体容积也会变小。两组参与者大脑容积的差异并不是由于药物滥用、抑郁或者外伤导致,目前研究者考虑进行统计学模型进行深入分析。

下一步,研究者计划去研究是否杏仁核容量变小是外伤导致的或者说是促使个体患PTSD的易损性所导致的。这项研究中,研究者阐明了杏仁核的容量并不是由于外伤的严重性以及持续时间所导致的,这也就揭示了外伤的暴露并不会引发杏仁核萎缩。研究结果显示杏仁核萎缩的患者更易患PTSD,但是研究者会继续进行研究来对这一结果进行确定。

研究者Morey说,我们会进行深入研究来揭示,是否杏仁核容量较小的个体会更易患PTSD障碍,这或许会帮助科学家们理解为何某些人群更易患PTSD,而有些人群则不易患病。而这项研究的结果帮助研究者离真相更近了一步。相关研究成果由国立卫生研究院等机构支持。(生物谷Bioon.com)

编译自:PTSD Linked to Smaller Brain Area Regulating Fear Response

Amygdala Volume Changes in Posttraumatic Stress Disorder in a Large Case-Controlled Veterans Group

Rajendra A. Morey, MD, MS; Andrea L. Gold, MS; Kevin S. LaBar, PhD; Shannon K. Beall, BS; Vanessa M. Brown, BA; Courtney C. Haswell, MS; Jessica D. Nasser, BA; H. Ryan Wagner, PhD; Gregory McCarthy, PhD; for the Mid-Atlantic MIRECC Workgroup

Context Smaller hippocampal volumes are well established in posttraumatic stress disorder (PTSD), but the relatively few studies of amygdala volume in PTSD have produced equivocal results. Objective To assess a large cohort of recent military veterans with PTSD and trauma-exposed control subjects, with sufficient power to perform a definitive assessment of the effect of PTSD on volumetric changes in the amygdala and hippocampus and of the contribution of illness duration, trauma load, and depressive symptoms. Design Case-controlled design with structural magnetic resonance imaging and clinical diagnostic assessments. We controlled statistically for the important potential confounds of alcohol use, depression, and medication use. Setting Durham Veterans Affairs Medical Center, which is located in proximity to major military bases. Patients Ambulatory patients (n = 200) recruited from a registry of military service members and veterans serving after September 11, 2001, including a group with current PTSD (n = 99) and a trauma-exposed comparison group without PTSD (n = 101). Main Outcome Measure Amygdala and hippocampal volumes computed from automated segmentation of high-resolution structural 3-T magnetic resonance imaging. Results Smaller volume was demonstrated in the PTSD group compared with the non-PTSD group for the left amygdala (P = .002), right amygdala (P = .01), and left hippocampus (P = .02) but not for the right hippocampus (P = .25). Amygdala volumes were not associated with PTSD chronicity, trauma load, or severity of depressive symptoms. Conclusions These results provide clear evidence of an association between a smaller amygdala volume and PTSD. The lack of correlation between trauma load or illness chronicity and amygdala volume suggests that a smaller amygdala represents a vulnerability to developing PTSD or the lack of a dose-response relationship with amygdala volume. Our results may trigger a renewed impetus for investigating structural differences in the amygdala, its genetic determinants, its environmental modulators, and the possibility that it reflects an intrinsic vulnerability to PTSD.

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