Combined, these altered resting-state connectivity and activity patterns could represent neurobiological correlates of increased salience processing and hypervigilance (SN), at the cost of awareness of internal thoughts and autobiographical memory (DMN) in PTSD. However, several discrepancies between findings of the meta-analysis and systematic review were observed, stressing the need for future studies on resting-state abnormalities in PTSD patients.

BACKGROUND Many studies report smaller hippocampal and amygdala volumes in posttraumatic stress disorder (PTSD), but findings have not always been consistent. Here, we present the results of a large-scale neuroimaging consortium study on PTSD conducted by the Psychiatric Genomics Consortium (PGC)–Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) PTSD Working Group. METHODS We analyzed neuroimaging and clinical data from 1868 subjects (794 PTSD patients) contributed by 16 cohorts, representing the largest neuroimaging study of PTSD to date. We assessed the volumes of eight subcortical structures (nucleus accumbens, amygdala, caudate, hippocampus, pallidum, putamen, thalamus, and lateral ventricle). We used a standardized image-analysis and quality-control pipeline established by the ENIGMA consortium. RESULTS In a meta-analysis of all samples, we found significantly smaller hippocampi in subjects with current PTSD compared with trauma-exposed control subjects (Cohen’s d = −0.17, p = .00054), and smaller amygdalae (d = −0.11, p = .025), although the amygdala finding did not survive a significance level that was Bonferroni corrected for multiple subcortical region comparisons (p < .0063). CONCLUSIONS Our study is not subject to the biases of meta-analyses of published data, and it represents an important milestone in an ongoing collaborative effort to examine the neurobiological underpinnings of PTSD and the brain’s response to trauma.

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The neuropeptide oxytocin (OT) has been suggested as a promising pharmacological agent for medication-enhanced psychotherapy in posttraumatic stress disorder (PTSD) because of its anxiolytic and prosocial properties. We therefore investigated the behavioral and neurobiological effects of a single intranasal OT administration (40 IU) in PTSD patients. We conducted a randomized, placebo-controlled, cross-over resting-state fMRI study in male and female police officers with (n = 37, 21 males) and without PTSD (n = 40, 20 males). We investigated OT administration effects on subjective anxiety and functional connectivity of basolateral (BLA) and centromedial (CeM) amygdala subregions with prefrontal and salience processing areas. In PTSD patients, OT administration resulted in decreased subjective anxiety and nervousness. Under placebo, male PTSD patients showed diminished right CeM to left ventromedial prefrontal cortex (vmPFC) connectivity compared with male trauma-exposed controls, which was reinstated after OT administration. Additionally, female PTSD patients showed enhanced right BLA to bilateral dorsal anterior cingulate cortex (dACC) connectivity compared with female trauma-exposed controls, which was dampened after OT administration. Although caution is warranted, our findings tentatively suggest that OT has the potential to diminish anxiety and fear expression of the amygdala in PTSD, either via increased control of the vmPFC over the CeM (males) or via decreased salience processing of the dACC and BLA (females). Our findings add to accumulating evidence that OT administration could potentially enhance treatment response in PTSD.

Oxytocin administration early after trauma did not attenuate clinician-rated PTSD symptoms in all trauma-exposed participants with acute distress. However, participants with high acute clinician-rated PTSD symptom severity did show beneficial effects of oxytocin. Although replication is warranted, these findings suggest that oxytocin administration is a promising preventive intervention for PTSD for individuals with high acute PTSD symptoms.

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Post-traumatic stress disorder (PTSD) is a disabling psychiatric disorder. As a substantial part of PTSD patients responds poorly to currently available psychotherapies, pharmacological interventions boosting treatment response are needed. Because of its anxiolytic and pro-social properties, the neuropeptide oxytocin (OT) has been proposed as promising strategy for treatment augmentation in PTSD. As a first step to investigate the therapeutic potential of OT in PTSD, we conducted a double-blind, placebo-controlled, cross-over functional MRI study examining OT administration effects (40 IU) on amygdala reactivity toward emotional faces in unmedicated male and female police officers with (n = 37, 21 males) and without (n = 40, 20 males) PTSD. Trauma-exposed controls were matched to PTSD patients based on age, sex, years of service and educational level. Under placebo, the expected valence-dependent amygdala reactivity (ie, greater activity toward fearful-angry faces compared with happy-neutral faces) was absent in PTSD patients. OT administration dampened amygdala reactivity toward all emotional faces in male and female PTSD patients, but enhanced amygdala reactivity in healthy male and female traumaexposed controls, independent of sex and stimulus valence. In PTSD patients, greater anxiety prior to scanning and amygdala reactivity during the placebo session were associated with greater reduction of amygdala reactivity after OT administration. Taken together, our results indicate presumably beneficial neurobiological effects of OT administration in male and female PTSD patients. Future studies should investigate OT administration in clinical settings to fully appreciate its therapeutic potential.

R. A. (2021). Altered white matter microstructural organization in posttraumatic stress disorder across 3047 adults: results from the PGC-ENIGMA PTSD consortium. Molecular Psychiatry,26,[4315][4316][4317][4318][4319][4320][4321][4322][4323][4324][4325][4326][4327][4328][4329][4330]