LSD vs psilocybin and brain blood flow: what do clinicians make of it?

A new study reported by Medical Xpress suggests that LSD and psilocybin shift blood flow in the brain in opposite directions. Both substances are being investigated as possible treatments for depression and other psychiatric disorders. This is only the authors' suggestion ("study suggests"): it does not imply any clinical benefit, and the short summary gives no details on study design or sample. What shall we discuss: — What could explain the different effects of two 5-HT2A agonists: binding to other receptors, pharmacokinetics, or the way blood flow was measured? — Can changes in cerebral blood flow tell us anything about a possible therapeutic effect, or are they more likely a side phenomenon? — Which neuroimaging limitations would you keep in mind when interpreting such results, and what would you want to see in the full paper? For USMLE and clinical practice, this is a good occasion to review the mechanism of serotonergic 5-HT2A agonists and what neuroimaging can and cannot show in psychopharmacology. Full article: drasiiavinograd.com/blog/lsd-vs-psilocybin-brain-blood-flow-usmle-5-ht Source: Medical Xpress medicalxpress.com/news/2026-10-lsd-psilocybin-brain-blood.html