Acute psilocybin effects on CBF and ICA diameter
Figshare January 1, 2026 DOI: 10.6084/m9.figshare.31064788.v1 via OpenAlex
Summary
AI-generated from the abstractPsilocybin reduces whole-brain cerebral blood flow and constricts the internal carotid artery in a dose-dependent manner. In 28 healthy participants given 0.2–0.3 mg/kg psilocybin, arterial spin labelling MRI showed widespread cortical blood flow decreases at peak plasma psilocin levels. Higher plasma psilocin concentrations correlated with lower cerebral blood flow and smaller carotid artery diameter, indicating that the drug's vascular effects are tied to its active metabolite.
Study at a glance
| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 28 |
| Population | Healthy human participants |
| Intervention | Psilocybin |
| Dose | 0.2–0.3 mg/kg |
| Topics | Psilocybin |
| Keywords | Cerebral blood flow Internal carotid artery Carotid arteries Anesthesia |
| Key finding | Psilocybin reduces whole-brain cerebral blood flow and internal carotid artery diameter in a dose-dependent manner, with higher plasma psilocin levels linked to greater reductions. |
Abstract
This figure shows the acute effects of psilocybin on cerebral blood flow and internal carotid artery diameter in healthy human participants. Whole-brain cerebral blood flow was measured using pseudo-continuous arterial spin labelling MRI at baseline, during the peak and late phases following psilocybin administration (0.2–0.3 mg/kg, N = 28). Cerebral blood flow maps illustrate widespread cortical reductions at peak plasma psilocin levels. Plasma psilocin concentrations were negatively associated with both whole-brain cerebral blood flow and internal carotid artery diameter, indicating dose-dependent effects. MRI acquisition, preprocessing, and statistical modelling procedures are described in detail in Larsen et al. (Journal of Cerebral Blood Flow & Metabolism, 2025).