Hulking purple creatures slinking around in the shadows, playing the bassoon. A distant aunt baking cookies on a flying steamship. Four brightly lit horses gingerly eating cake from a giant spoon. There’s nothing like a weird dream and the air of surreal strangeness that lingers when you wake up.
But researchers disagree with the idea that nighttime hallucinations are a singular sensation. Camila Sanz and Enzo Tagliazucchi explored the possibility that they are, in fact, an almost identical experience to tripping on certain drugs. Descriptions of trips as being dreamlike and vice versa, they argue, are more than just simple comparisons—they’re signifiers of a bigger connection between dreaming and drugs and the underlying mechanisms that drive both.
Clarity in Dreams
Nearly every hallucinogen or dream-related movie sequence relies on the experience of “cognitive bizarreness,” the weird things the brain comes up with when it’s uninhibited. The crew in Easy Rider didn’t just go to a cemetery to trip and see one another sit around. Fear and Loathing in Las Vegas didn’t have Hunter S. Thompson just do a bunch of drugs and experience being in an office building or something. With that many substances around, things in the brain are bound to get weird. And at least when it comes to certain substances, they get very dreamy indeed.
The researchers found that it’s serotonergic hallucinogens—drugs like LSD, peyote, ayahuasca, psilocybin, etc.—that produce a state most reliably resembling dreaming. Sanz and Tagliazucchi analyzed thousands of posts on both Dream Journal and Erowid to see what words and concepts appeared most frequently in dreamers and users of the drugs profiled. The results were turned into word clouds, and then each of the 165 drug clouds and the two dream clouds were compared.
Dreams were separated into two types: those of low- and high-lucidity. Lucid dreams, as high-lucidity ones are known, involve a greater deal of awareness—what the researchers call “metacognition”—about being in an altered state. It’s your ability to figure out that you’re dreaming and possibly bend the circumstances of an otherwise untethered imagination to your will. If regular dreams are like watching a movie, lucid dreams are like playing a video game.
Besides serotonergics, low-lucidity dreams especially showed a connection with a class of drugs known as deliriants (including Datura, which is often confused for morning glory, mandrake and, interestingly, uncured tobacco). Unlike serotonergic hallucinogens, during which people can maintain this metacognition, deliriants “are called [that] because their subjective effects are similar to the experiences of people with delirious fevers,” resulting in a less lucid state and therefore an increased similarity to low-lucidity dreams. Trips on deliriants are described as weaving “seamlessly into waking consciousness, similar to fully formed dreams or delusions.”
(Interestingly, cannabis too made the top of the list, coming in as the fifth-most similar drug to both low- and high-lucidity dreams.)
The reason for these similarities—at least when it comes to serotonergics, the most heavily studied of the dream-like drugs—is rooted firmly in the human brain. Both REM sleep (which is when dreams mostly occur) and serotonergic trips involve the same serotonin receptors. Because these are located in the part of the brain linked to processing visual information, modified neuron action can cause experiences of a “highly visual nature.” This neuron shift also causes brainwaves to start oscillating in different patterns, leading to increased intensity of the visual imagery. And, to top it off, serotonergic hallucinogens disrupt “inhibitory processes in the brain,” messing with the way that parts of the organ (like the medial temporal lobe, which deals with visual memory and interpretation) work. In short, serotonergic trips and dreams can bombard you with visuals without allowing you to use the equipment that would process them.
The result of these intense experiences can be significant. It’s “long been known [that serotonergics can] induce ego dissolution experiences, which have been sometimes ascribed a spiritual or mystical character.” Divisions between the self and the external are lost and the self leaks into the outside world like the viscous liquid of a shattered lava lamp. And though it hasn’t been studied the way that psychedelic and hallucinogen-related ego changes have, ego death during sleep has certainly been reported anecdotally. These accounts note a shift in self-awareness “related either to the dissociation between the first-person point of view and the bodily self or to the loss of boundaries between the bodily self and the environment.”
It’s on the matter of ego and self-awareness, the researchers say, that dream states and tripping have their most critical overlap. They suggest this relationship might even extend into “certain spontaneously occurring altered states of consciousness [such as near-death experiences],” which they say may be “induced by psychedelic compounds endogenous to the human brain.”
As it stands, despite its singular effect upon the human experience, most of the existing research on ego death (largely in the context of hallucinogens and psychedelics) has not been pivoted towards exploring related biological systems and phenomena. In a sense, Sanz and Tagliazucchi’s research is about much more than simply seeing what drugs will cause a dream-like trip. It’s about how our brain interacts with the chemicals in these drugs and whether that suggests an underlying mechanism for dreaming that we may not yet understand. It’s about how the similarities between these drugs and dreaming are driven specifically by “changes in self-awareness” and what we can discover about how our sense of self manifests physically within the brain. Certainly much is left up in the air after this study—and it’s by no means a definitive scientific revelation—but the dark side of the mind is a fascinating road upon which to embark, and these researchers have unapologetically gotten the car rolling.