Reduced amygdala serotonin transporter binding in posttraumatic stress disorder.

The amygdala is a key site where alterations in the regulation of the serotonin transporter (5-HTT) may alter stress response. Deficient 5-HTT function and abnormal amygdala activity have been hypothesized to contribute to the pathophysiology of posttraumatic stress disorder (PTSD), but no study has evaluated the 5-HTT in humans with PTSD. On the basis of translational models, we hypothesized that patients diagnosed with PTSD would exhibit reduced amygdala 5-HTT expression as measured with positron emission tomography and the recently developed 5-HTT-selective radiotracer [(11)C]AFM. Fifteen participants with PTSD and 15 healthy control (HC) subjects without trauma history underwent a resting-state positron emission tomography scan. [(11)C]AFM binding potential (BP(ND)) within the combined bilateral amygdala region of interest was significantly reduced in the PTSD group compared with the HC group (p = .027; 16.3% reduction), which was largely driven by the between-group difference in the left amygdala (p = .008; 20.5% reduction). Furthermore, amygdala [(11)C]AFM BP(ND) was inversely correlated with both Hamilton Rating Scale for Anxiety scores (r = -.55, p = .035) and Montgomery-Åsberg Depression Rating Scale scores (r = -.56, p = .029). Our findings of abnormally reduced amygdala 5-HTT binding in PTSD and its association with higher anxiety and depression symptoms in PTSD patients support a translational neurobiological model of PTSD directly implicating dysregulated 5-HTT signaling within neural systems underlying threat detection and fear learning. Copyright © 2011 Society of Biological Psychiatry. All rights reserved.

Citation

James W Murrough, Yiyun Huang, Jian Hu, Shannan Henry, Wendol Williams, Jean-Dominique Gallezot, Christopher R Bailey, John H Krystal, Richard E Carson, Alexander Neumeister. Reduced amygdala serotonin transporter binding in posttraumatic stress disorder. Biological psychiatry. 2011 Dec 1;70(11):1033-8

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PMID: 21855859

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