OPEN Foundation

L. Averill

Psychedelic Treatment for Trauma-Related Psychological and Cognitive Impairment Among US Special Operations Forces Veterans

U.S. Special Operations Forces Veterans are at increased risk for a variety of mental health problems and cognitive impairment associated with military service. Current treatments are lacking in effectiveness and adherence. Therefore, this study examined psychedelic treatment with ibogaine and 5-methoxy-N,N-dimethyltryptamine for trauma-related psychological and cognitive impairment among U.S. Special Operations Forces Veterans.

We conducted a survey of Veterans who completed a specific psychedelic clinical program in Mexico between 2017 and 2019. Questions probed retrospective reports of mental health and cognitive functioning during the 30 days before and 30 days after treatment. A total of 65 people completed treatment during this time frame and were eligible for contact. Of these, 51 (78%) completed the survey and were included in data analyses (mean age = 40; male = 96%; married = 55%; Caucasian/White = 92%; Operation Enduring Freedom/Operation Iraqi Freedom Service = 96%).

Results indicated significant and very large reductions in retrospective report of suicidal ideation (p < .001; d = −1.9), cognitive impairment (p < .001; d = −2.8), and symptoms of posttraumatic stress disorder (p < .001; d = −3.6), depression (p < .001; d = −3.7), and anxiety (p < .001; d = −3.1). Results also showed a significant and large increase in retrospective report of psychological flexibility (p < .001; d = 2.9) from before-to-after the psychedelic treatment. Increases in the retrospective report of psychological flexibility were strongly associated with retrospective report of reductions in cognitive impairment, and symptoms of posttraumatic stress disorder, depression, and anxiety (rs range −0.61 to −0.75; p < .001). Additionally, most participants rated the psychedelic experiences as one of the top five personally meaningful (84%), spiritually significant (88%), and psychologically insightful (86%) experiences of their lives.
Limitations: Several limitations should be considered including the retrospective, self-report, survey design of the study, and the lack of randomization and blinding, thus making these finding preliminary.

U.S. Special Operations Forces Veterans may have unique treatment needs because of the sequela of problems associated with repeated trauma exposure and the nature of the exposure. Psychedelic-assisted therapy with these under-researched psychedelics may hold unique promise for this population. However, controlled studies are needed to determine whether this treatment is efficacious in relieving mental health and cognitive impairment among U.S. Special Operations Forces Veterans.

Davis, A. K., Averill, L. A., Sepeda, N. D., Barsuglia, J. P., & Amoroso, T. (2020). Psychedelic Treatment for Trauma-Related Psychological and Cognitive Impairment Among US Special Operations Forces Veterans. Chronic Stress4, 2470547020939564; 10.1177/2470547020939564
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Synaptic Loss and the Pathophysiology of PTSD: Implications for Ketamine as a Prototype Novel Therapeutic


Studies of the neurobiology and treatment of PTSD have highlighted many aspects of the pathophysiology of this disorder that might be relevant to treatment. The purpose of this review is to highlight the potential clinical importance of an often-neglected consequence of stress models in animals that may be relevant to PTSD: the stress-related loss of synaptic connectivity.
Here, we will briefly review evidence that PTSD might be a “synaptic disconnection syndrome” and highlight the importance of this perspective for the emerging therapeutic application of ketamine as a potential rapid-acting treatment for this disorder that may work, in part, by restoring synaptic connectivity. Synaptic disconnection may contribute to the profile of PTSD symptoms that may be targeted by novel pharmacotherapeutics.
Krystal, J. H., Abdallah, C. G., Averill, L. A., Kelmendi, B., Harpaz-Rotem, I., Sanacora, G., … & Duman, R. S. (2017). Synaptic loss and the pathophysiology of PTSD: implications for ketamine as a prototype novel therapeutic. Current Psychiatry Reports19(10), 74. 10.1007/s11920-017-0829-z
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Prefrontal Connectivity and Glutamate Transmission: Relevance to Depression Pathophysiology and Ketamine Treatment



Prefrontal global brain connectivity with global signal regression (GBCr) was proposed as a robust biomarker of depression and was associated with ketamine’s mechanism of action. Here, we investigated prefrontal GBCr in treatment-resistant depression (TRD) at baseline and following treatment. Then, we conducted a set of pharmacological challenges in healthy subjects to investigate the glutamate neurotransmission correlates of GBCr.


In the cohort A study, we used functional magnetic resonance imaging to compare GBCr between 22 patients with TRD and 29 healthy control subjects. Then, we examined the effects of ketamine and midazolam on GBCr in patients with TRD 24 hours posttreatment. In the cohort B study, we acquired repeated functional magnetic resonance imaging in 18 healthy subjects to determine the effects of lamotrigine (a glutamate release inhibitor), ketamine, and lamotrigine-by-ketamine interaction.


In the cohort A study, patients with TRD showed significant reduction in dorsomedial and dorsolateral prefrontal GBCr compared with healthy control subjects. In patients with TRD, GBCr in the altered clusters significantly increased 24 hours following ketamine (effect size = 1.0, confidence interval = 0.3 to 1.8) but not following midazolam (effect size = 0.5, confidence interval = −0.6 to 1.3). In the cohort B study, oral lamotrigine reduced GBCr 2 hours postadministration, while ketamine increased medial prefrontal GBCr during infusion. Lamotrigine significantly reduced the ketamine-induced GBCr surge. Exploratory analyses showed elevated ventral prefrontal GBCr in TRD and significant reduction of ventral prefrontal GBCr during ketamine infusion in healthy subjects.


This study provides the first replication of the ability of ketamine to normalize depression-related prefrontal dysconnectivity. It also provides indirect evidence that these effects may be triggered by the capacity of ketamine to enhance glutamate neurotransmission.

Abdallah, C. G., Averill, C. L., Salas, R., Averill, L. A., Baldwin, P. R., Krystal, J. H., … & Mathalon, D. H. (2017). Prefrontal Connectivity & Glutamate Transmission: Relevance to Depression Pathophysiology and Ketamine Treatment. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. 10.1016/j.bpsc.2017.04.006
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Ketamine Treatment and Global Brain Connectivity in Major Depression


Capitalizing on recent advances in resting state functional connectivity magnetic resonance imaging (rs-fcMRI) and the distinctive paradigm of rapid mood normalization following ketamine treatment, the current study investigated intrinsic brain networks in major depressive disorder (MDD) during a depressive episode and following treatment with ketamine. Medication-free patients with MDD and healthy control subjects (HC) completed baseline rs-fcMRI. MDD patients received a single infusion of ketamine and underwent repeated rs-fcMRI at 24 h post-treatment. Global brain connectivity with global signal regression (GBCr) values were computed as the average of correlations of each voxel with all other gray matter voxels in the brain. MDD group showed reduced GBCr in the prefrontal cortex (PFC), but increased GBCr in the posterior cingulate, precuneus, lingual gyrus, and cerebellum. Ketamine significantly increased GBCr in the PFC and reduced GBCr in the cerebellum. At baseline, 2174 voxels of altered GBCr were identified, but only 310 voxels significantly differed relative to controls following treatment (corrected α<0.05). Responders to ketamine showed increased GBCr in the lateral PFC, caudate, and insula. Followup seed-based analyses illustrated a pattern of dysconnectivity between the PFC/subcortex and the rest of the brain in MDD, which appeared to normalize post-ketamine. The extent of the functional dysconnectivity identified in MDD and the swift and robust normalization following treatment, suggest that GBCr may serve as a treatment response biomarker for the development of rapid acting antidepressants. The data also identified unique prefrontal and striatal circuitry as putative marker of successful treatment and target for antidepressants development.

Abdallah, C. G., Averill, L. A., Collins, K. A., Geha, P., Schwartz, J., Averill, C., … & Iosifescu, D. V. (2016). Ketamine Treatment and Global Brain Connectivity in Major Depression. Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology. 10.1038/npp.2016.186

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Ketamine as a promising prototype for a new generation of rapid-acting antidepressants


The discovery of ketamine’s rapid and robust antidepressant effects opened a window into a new generation of antidepressants. Multiple controlled trials and open-label studies have demonstrated these effects across a variety of patient populations known to often achieve little to no response from traditional antidepressants. Ketamine has been generally well tolerated across patient groups, with transient mild-to-moderate adverse effects during infusion. However, the optimal dosing and route of administration and the safety of chronic treatment are not fully known. This review summarizes the clinical effects of ketamine and its neurobiological underpinnings and mechanisms of action, which may provide insight into the neurobiology of depression, relevant biomarkers, and treatment targets. Moreover, we offer suggestions for future research that may continue to advance the field forward and ultimately improve the psychopharmacologic interventions available for those individuals struggling with depressive and trauma-related disorders.

Abdallah, C. G., Averill, L. A. and Krystal, J. H. (2015), Ketamine as a promising prototype for a new generation of rapid-acting antidepressants. Annals of the New York Academy of Sciences, 1344: 66–77. doi: 10.1111/nyas.12718

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