Psilocybin mushrooms have helped human beings unlock their egos for centuries. This video, Psychedelic Science: Psilocybin by Reason TV, features interviews with two leading researchers who explain what we know about the magic mushroom effect and how much more we have to learn.

“These are remarkable compounds, with I think remarkable implications, if we can understand how they work and why they work,” says Roland Griffiths, a scientist at Johns Hopkins University, where some of the world’s leading psychedelic research is taking place.

Psilocybin mushrooms provoke mystical experiences and spiritual journeys when the body breaks the chemical down into a compound that is very similar to serotonin, a natural neurotransmitter in the brain. But psilocybin and serotonin aren’t exactly the same, explains Robin Carhart-Harris of the Imperial College London, and “that subtle difference in its pharmacology confers profound effects on consciousness.”

“What seems to happen in the psychedelic state is that when something is positive, it has the potential to be incredibly positive, to the extent of being euphoric, or ecstatic,” Carhart-Harris says. “But similarly if something is negative, it has the potential to be quite hellish and dysphoric and frightening.”

Griffith led a study published in 2006 in which volunteers received psilocybin or a comparative drug and were allowed to relax with soothing music in the presence of people with whom they had a trusting relationship.

“Under those conditions, a high percentage of people end up reporting a constellation of experiences,” he says, “the most interesting piece of which is that it really falls into a category of something that psychology of religion people talk about as a primary mystical experience.”

The fact that the brain reacts to the chemical in such a way is telling. “One of the interesting implications of this kind of work is that we’re biologically hard-wired for having these kinds of experiences,” says Griffiths. “It’s not just unique to mystics spending years of meditation in a cave. This is part of the human biology to have these kinds of integrative experiences that can really set the stage and the platform for remarkable personal change.”

The potential of mushrooms goes beyond mysticism, however. Subsequent research used brain imaging technology like functional magnetic resonance imaging, which uses magnets to monitor changes in the brain while subjects were under the influence of psilocybin. Scientists found decreased activity in a region of the prefrontal cortex that is highly active in depression.

Conventional depression treatments seek to normalize the overactivity in that area, and the mushrooms have the same effect. “Psilocybin did exactly that, and it did it very rapidly,” Carhart-Harris says.

Johns Hopkins is now studying psilocybin in cancer patients who are suffering from anxiety or depression from a life-threatening diagnosis. “That sadness is still there,” says Griffiths, “but there’s also a larger framing of that, and so it’s very touching.”

It’s clear we’ve only scratched the surface of how mushrooms effect the brain and can be used to benefit humanity. “There’s a growing consensus among scientists that drug laws and prohibition around psychedelic drugs is irrational,” Carhart-Harris says, “it’s unhelpful, and it potentially is precluding people who are unwell from getting effective treatment.”