There’s a gateway in the middle of your brain that prevents you from fully experiencing every sense that hits you throughout the day. Called the thalamus, it sits on top of the brain stem and decides which sensory information, including what you’re hearing, what you’re touching, and what you’re seeing, is important and which isn’t, giving the non-essential stuff the boot. Without the thalamus doing its job, your brain would be completely overloaded. Without it functioning at 100, you’re as good as tripping.
One of the leading theories about what LSD (a.k.a. lysergic acid diethylamide, a.k.a. acid) does is that it inhibits the thalamus’s ability to act as that filter, thus propelling you into that tripping state. A study published in the scientific journal PNAS in February backs that theory up, giving us an even better idea of how LSD works.
Researchers led by Katrin H. Preller, Ph.D., of the University of Zurich put 25 people on acid and monitored their brain waves. They found that LSD altered the connectivity between the thalamus and other parts of the brain—in particular, increasing connectivity with cortex areas that handle our senses.
“We tested a model that tries to explain how psychedelics work in the brain based on animal studies and that had been around for about 20 years. We showed that this model holds mostly true in humans: The thalamus, which is usually filtering information, sends more information to certain areas in the cortex,” Preller told PsyPost. “This can explain why psychedelics induce the overwhelming feelings that participants report.”
Serotonin, a neurotransmitter that affects mood and has long been connected with LSD, was found to play an important role in the new research as well. When researchers blocked serotonin receptors in participants’ brains and gave them acid, the acid did not cause the participants to experience any psychedelic effects.
It’s all to say that when we humans take LSD, it causes our brains to absorb much more of what we’re seeing, hearing, and otherwise sensing, and all that extra information is pretty damn mind-bending. The hallucinogenic power is strong and often long-lasting. The experience can also be incredibly useful.
Preller and other researchers believe understanding LSD could lead to groundbreaking work with psychiatric disorders like schizophrenia, depression, and OCD, which all involve complex connections between the thalamus and the cortex, and serotonin reactions. “For disorders with increased self-focus such as depression or anxiety disorders, stimulating serotonin 2A receptors with psychedelics might indeed be beneficial,” Preller told Gizmodo about previous research she has conducted on LSD.
Other studies and anecdotal evidence indicate that LSD helps patients suffering from anxiety, addiction, and depression. On a larger psychedelic scale, ecstasy has been used to help military veterans deal with PTSD. Psilocybin, the active compound in magic mushrooms, has similarly been linked to helping people with addiction, anxiety, and depression.
This vein of research is getting even the more straight-laced among us interested in acid. Microdosing is something of a wellness craze, with tech bros and creatives alike taking small bits of LSD or shrooms throughout the day to feel less depressed, more calm, and more productive. There’s even a psilocybin legalization effort making headway in Denver, Colorado, and Oregon. (Psychedelic drugs are all 100-percent illegal.)
LSD was cooked up in a lab over 80 years ago. Scientists were digging into its potential—even Cary Grant said he took it and loved it at an LSD clinic in the late ’50—before the counterculture got its hands on it in the ’60s, scaring the government away from supporting more research. Hunter S. Thompson kept its infamy alive and well in later decades, as did his acolyte Johnny Depp. These days, it’s back in focus for experts who think it can make a difference for some people, and they’re finally getting clearance to test out their hypotheses. The more we know about LSD, the better. It’s not all bad trips and acid flashbacks.