Delayed psilocybin treatment after repeated mild traumatic brain injury recovers chronic behavioural deficits, reduces microglial density, and enhances hippocampal neurogenesis in rats
Research Square February 23, 2026 Sandy R. Shultz, Josh Allen, Grace O'Regan et al.
Repeated mild traumatic brain injury in rats produced lasting deficits in mood, social behavior, and pain sensitivity. Delayed treatment with psilocybin (1 mg/kg) reversed several of these effects, including antidepressant-like effects, increased social behavior, and raised pain thresholds. Psilocybin also reduced injury-related increases in microglial density and increased the number and complexity of newborn neurons in the dentate gyrus, suggesting enhanced neuroplasticity. The findings indicate psilocybin may be a promising intervention for persistent symptoms after repeated mild traumatic brain injury.