This open-label retreat study (n=21) of veterans with traumatic brain injuries tested dried psilocybin mushrooms (1.5–5g) in two ceremonies over six days. Four weeks later, PTSD, depression, and anxiety scores fell by 50%, 65%, and 28% respectively, while EEG showed reduced delta/theta power and increased alpha/beta coherence, suggesting improved emotional regulation and cognition.
Abstract of Improved mental health outcomes and normalised spontaneous EEG activity in veterans reporting a history of traumatic brain injuries following participation in a psilocybin retreat
“Introduction: Psilocybin, a serotonergic psychedelic, has shown therapeutic potential in treating mental health disorders by, amongst the many effects, promoting neuroplasticity and reorganising functional connectivity across cortical and subcortical networks involved in emotion and cognition. Veterans with traumatic brain injuries (TBI) often experience chronic neurological and psychological symptoms such as post-traumatic stress disorder (PTSD) and depression. This study investigates the effects of psilocybin administered in retreat settings on veterans with a history of TBI, focusing on mental health outcomes and changes in brain connectivity as measured by EEG.
Methods: A total of 21 participants were recruited through the Heroic Hearts Project, which facilitated access to two six-day psilocybin retreats in Jamaica. Before the retreat, participants underwent three individual and three group coaching sessions to prepare for the experience. During the retreat, two psilocybin ceremonies were held, spaced 48 hours apart. Participants received an initial dose of 1.5g to 3.5g of dried psilocybin mushrooms, with the option to increase the second dose up to 5g. Psilocybin was administered in a tea format, under the supervision of experienced facilitators. Psychological outcomes were assessed using validated questionnaires (PCL-5, PHQ-9, STAI) at baseline (four weeks pre-retreat) and four weeks post-retreat. Electroencephalography (EEG) was used to measure brainwave activity pre- and post-treatment. Paired t-tests were used to analyze changes in psychological scores, while EEG frequency band analysis assessed changes in brain function and connectivity.
Results: Improvements were observed across several mental health measures: PTSD (PCL-5 scores decreased by 50%, p=0.010), depression (PHQ-9 scores decreased by 65%, p<0.001), and anxiety (STAI) scores decreased by 28%, p<0.001). EEG data showed decreased delta and theta power in frontal and temporal regions, indicating potential improvements in cognitive control and emotional processing. Enhanced coherence in alpha and beta bands suggested improved neural communication.
Discussion: The study suggests that psilocybin retreats might provide improvements in psychological well-being and brain connectivity in veterans with TBI. Reduced delta power and normalised theta activity suggest better emotional regulation, while improved coherence in alpha and beta bands may reflect increased cognitive engagement. Further, these preliminary outcomes provide a potential rationale for the design and implementation of larger-scale, controlled studies to validate and expand upon these initial findings.“
Authors: Grace Blest-Hopley, Giuseppe Pasculli, Simon G. D. Ruffell, WaiFung Tsang, Olateju Emmanuel, Kathryn M. Pate, Hannes Kettner, Leor Roseman, David Erritzoe & Robin L. Carhart-Harris
Summary of Improved mental health outcomes and normalised spontaneous EEG activity in veterans reporting a history of traumatic brain injuries following participation in a psilocybin retreat
The article opens by situating the study within the renewed scientific interest in psychedelic-assisted therapies. Psychedelics such as psilocybin, MDMA, ayahuasca, and LSD have gained attention for their potential to treat a range of mental health conditions including depression, anxiety, and post-traumatic stress disorder. The authors explain that these substances work partly through serotonin receptors in the brain, especially the 5-HT2A receptor, which plays a role in mood and perception.
The introduction highlights a specific focus on eating disorders, which are highly disabling mental health conditions with limited treatment options and high relapse rates. Traditional therapies, such as cognitive-behavioural therapy, often fall short in producing sustained recovery. Psychedelics, with their capacity to enhance emotional processing and create lasting psychological insights, are being considered as possible novel interventions. Previous studies have shown promising results in related disorders, such as obsessive-compulsive disorder and substance use problems, suggesting a potential application to eating disorders.
The authors point out that, despite the emerging enthusiasm, very little is known about how people with eating disorders perceive psychedelic use, particularly outside controlled research settings. To address this gap, the study explores the self-reported experiences of individuals with eating disorders who have used psychedelics, aiming to uncover perceived benefits, challenges, and possible therapeutic value.
Methods
Study Design and Recruitment
Find this paper
https://doi.org/10.3389/fpsyt.2025.1594307
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Cite this paper (APA)
Blest-Hopley, G., Pasculli, G., Ruffell, S. G., Emmanuel, O., Pate, K. M., Kettner, H. S., ... & Carhart-Harris, R. (2025). Improved mental health outcomes and normalized spontaneous EEG activity in veterans reporting a history of Traumatic Head Injuries following participation in a psilocybin retreat. Frontiers in Psychiatry, 16, 1594307.
Study details
Compounds studied
Psilocybin
Topics studied
Traumatic Brain Injury
Neuroscience
Study characteristics
Open-Label
Bio/Neuro
Participants
21
Humans
Compound Details
The psychedelics given at which dose and how many times
Psilocybin 1.5 - 3.5mg | 2x