Psychedelics, explained in scenes

Mushrooms, LSD, ayahuasca, peyote and their relatives: where they come from, what they do in your brain, and what they mean, in short animated scenes. Then uncover the chapters that go deeper. Every fact sourced.

Meet the psychedelics

Every one, in a minute: where it comes from, what it does, what it means.

  • A handful of molecules can change what you see, who you feel you are, and what you believe. Meet them.
  • Mushrooms. Aztec healers used them in rituals for healing and divination.
  • In your brain it fits one of serotonin's locks, and for about six hours the world starts to breathe.
  • In a trial with people facing cancer, it brought large, lasting drops in depression and anxiety.
  • Made in a lab. Its power was discovered by accident, in 1943.
  • A dose of a tenth of a milligram lasts about eight hours.
  • Soon after its discovery, it set researchers studying serotonin in the brain.
  • A brew with a long history among native peoples of the Amazon.
  • Its DMT would be destroyed in your gut on its own. The brew's other compounds shield it, so it reaches the brain.
  • Injected, DMT peaks within two minutes and is almost gone in thirty.
  • From the peyote cactus, used for millennia, and a sacrament of the Native American Church.
  • The longest of the classic three: about eleven hours.
  • A relative, not a classic psychedelic: it makes serotonin pour out of nerve cells.
  • In a PTSD trial, 67% no longer met criteria after three sessions, against 32% with placebo.
  • An anesthetic that blocks a different lock, the NMDA receptor.
  • A form of it, esketamine, is now an approved treatment for depression that hasn't responded to anything else.
  • A plant whose active compound works on a completely different receptor, kappa-opioid, often for fifteen minutes or less.
  • Psilocybin, LSD, DMT and mescaline all switch on the same lock: the serotonin 5-HT2A receptor.
  • What that one lock does to your vision, your sense of self and what you believe is stranger still. Keep exploring.

What you'd see

Why everyone sees the same tunnels and spirals, and how to make them yourself.

  • An ordinary room. First, the colours get richer and the light brighter.
  • Then textures start to move, and surfaces seem to breathe.
  • Moving lights leave trails of separate afterimages.
  • At strong doses, geometric patterns spread over everything.
  • People on mushrooms or LSD, in migraines, even pressing on their eyes, see the same few shapes: tunnels, spirals, lattices.
  • They're the shape of your visual cortex. Excited, it makes stripes; seen through how your eye maps onto it, stripes become tunnels and spirals.
  • Try it: turn the stripes on the cortex and watch what you'd see.

The self, dissolving

Who are you, when the sense of "you" switches off?

  • You feel like a "you": one person, separate from everything around you.
  • That sense is tied to a set of brain regions called the default mode network.
  • Psilocybin blurs the boundaries between the brain's networks, most of all this one, and the more it does, the stronger the experience.
  • At high doses, people say the self simply stops: "all notion of self and identity dissolved away".
  • The higher the dose, the more it dissolves. Cocaine and alcohol don't do this.
  • Fourteen months after one supervised session, 58% ranked it among the five most meaningful experiences of their lives.
  • If the self can switch off while experience carries on, what is a self? Some philosophers think it's the brain binding experience to a lasting "me", and here the binding slips.

The quiet brain

Why the brain goes quieter, not louder.

  • You'd expect a brain on psilocybin to light up like a firework.
  • In a 2012 study, its activity only went down, most of all in hubs like the thalamus and the cingulate.
  • One theory: ordinary waking consciousness is held in a tight, constrained pattern. That's what gives us reality-testing and a sense of self.
  • Psychedelics loosen it. Activity grows more disordered and roams a far wider range of patterns.
  • In the 1950s, Aldous Huxley imagined the brain as a "reducing valve", letting only a trickle of a much larger mind through.
  • The new theory sounds a lot like his. So does the brain make the mind, or filter it?

When it goes wrong

The real risks, and how people guard against them.

  • The most likely problem is a terrifying trip.
  • In one survey of people's worst trips, 11% had put themselves or others at risk.
  • Psilocybin can worsen mental illness in people who have, or are prone to, psychotic disorders.
  • In reports of psychedelics taken on lithium, nearly half described seizures.
  • Misidentified wild mushrooms cause most mushroom deaths.
  • Rarely, the visuals carry on for months or years afterwards, most often after illicit LSD.
  • Research sessions guard against harm with screening, preparation, a safe place and trusted people.
  • Physically, psilocybin is among the least toxic drugs. The risks are in the mind, and in what people do.