Ketamine and serotonergic psychedelics: An update on the mechanisms and biosignatures underlying rapid-acting antidepressant treatment
Neuropharmacology January 13, 2023 Jenessa N. Johnston, Bashkim Kadriu, Josh Allen et al. 64 citations
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Josh Allen
Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.
5 papers in the library · 74 citations · publishing 2023-2026
Papers
Can the gut-brain axis provide insight into psilocybin's therapeutic value in reducing stress?
Neurobiology of Stress May 1, 2025 Alanna Kit, Kate Conway, Savannah Makarowski et al. 5 citations
Psilocybin shows therapeutic potential for stress-related neuropsychiatric disorders like depression, anxiety, PTSD, OCD, addiction, and eating disorders, but its mechanisms are complex, involving multiple body systems. This review explores how psilocybin interacts with the gut microbiota, enteric nervous system, and hypothalamic-pituitary axis, influencing bidirectional communication between peripheral and neuronal systems. Understanding these gut-brain interactions could advance psilocybin-based therapies from preparation through long-term integration, potentially extending benefits beyond psychiatric disorders to inflammatory-related conditions.
Examining the potential of psilocybin and 5-MeO-DMT as therapeutics for traumatic brain injury.
Progress in neuro-psychopharmacology & biological psychiatry July 14, 2025 Zoe Plummer, Josh Allen, Justin Brand et al. 4 citations
Traumatic brain injury (TBI) causes neuroinflammation, oxidative stress, impaired neuroplasticity, neurotransmitter imbalances, and cell death, leading to neurological and psychiatric disorders. The serotonergic psychedelics psilocybin and 5-MeO-DMT may help treat TBI by promoting neuroplasticity, reducing inflammation, and protecting neurons. Psilocybin acts through 5-HT1A, 5-HT2A, and neurotrophic TrkB receptors, while 5-MeO-DMT targets sigma-1 receptors with neuroprotective properties. Preclinical and clinical research suggests these compounds can alleviate cognitive and affective dysfunction and neuroinflammation after TBI. The review critically examines safety, dosing, and clinical challenges, highlighting the potential of these psychedelics as adjunctive treatments in neurorehabilitation.
Psilocybin mitigates chronic behavioral and neurobiological alterations in a rat model of recurrent intimate partner violence-related brain injury.
Molecular psychiatry April 1, 2026 Josh Allen, Mujun Sun, Tamara L Baker et al. 1 citation
In a rat model of recurrent intimate partner violence brain injury (daily mild traumatic brain injury plus non-fatal strangulation for five days followed by 16 weeks of recovery), a single dose of psilocybin (1 mg/kg) reversed injury-induced anxiety-like behavior in the elevated plus-maze, increased sucrose preference (indicating reduced anhedonia), and improved reversal learning in the water maze and spatial memory in the Y-maze. Psilocybin also prevented the increase in microglial cells in the dorsal hippocampal molecular layer and the loss of reelin-positive cells in the subgranular zone seen in saline-treated injured rats. Pre-treatment with a 5-HT2A receptor antagonist blocked psilocybin's behavioral effects, indicating these benefits depend on 5-HT2A receptor activation.
Psilocybin restores behavior and 5-HT2A signaling while reducing microglial density after chronic traumatic brain injury in rats.
Cell reports. Medicine June 12, 2026 Josh Allen, Bianca Jupp, Tamara L Baker et al.
One year after a fluid-percussion traumatic brain injury, male rats showed persistent sensorimotor, learning, memory, and affective deficits; reduced serotonin 2A receptor binding; and microglial changes in the medial prefrontal cortex, including decreased process branching and enlarged soma size. A single dose of psilocybin (1 mg/kg) improved sensorimotor function, restored serotonin 2A receptor binding, and reduced microglial cell counts. These results suggest psilocybin has therapeutic potential for chronic traumatic brain injury and support further investigation of psychedelic treatments.