Many current migraine treatments (such as triptans and ergotamine) are serotonin agonists designed to induce vasoconstriction. The &quot;classic psychedelics&quot; are also serotonin agonists.<p>Migraine treatments target different subparts of the serotonin system than psychedelics do (migraine: primarily 5HT1B&#x2F;5HT1D vs psychedelics: 5HT2A). However, from what I see, a lot of the classic &quot;popular psychedelics&quot; don&#x27;t tend to be very selective, and act on a lot of the serotonin system as well as other systems such as glutamate (5HT2A agonism by itself is not necessarily psychedelic).<p>Consequently, LSD for instance seems to have quite an affinity for 5HT1B (with a touch of 5HT1D), and psilocin for 5HT1D (and a touch of 5HT1B). So reports of LSD and psilocin being effective against migraines aren&#x27;t surprising.