The Science of Seeing Dead People- AKA Hallucinations
A woman shrieked in Terry’s ear. He sprinted down the stairs. “Grandma!” He begged. “Grandma! I’m sorry!”
“VILE CHILD! PATHETIC WHELP!” She wailed into his ears.
“I’m sorry!” Terry tried to outrun the voice, but he missed a step and toppled to the cold tile floor of the kitchen. His head swam under the wailing. “Grandma! Why won’t you tell me what I did wrong?!”
The woman shrieked, “SCUM! SCUM! SCUM!” That was the last thing Terry heard as darkness enveloped his vision.
“T…Erry? Terry? You okay?”
Terry felt cold fingers tap his face. “Terry?” His sister, Lila asked again. “Welcome back to the land of the living, it seems.”
Terry peeled open his eyes. He was under a tree beside their grandparent’s old home. “W-where…?” He sputtered. His head ached and felt heavier than a bowling ball.
“Where what?”
“Ghost… Screaming…Grandma…”
Lila shook her head. “Grandma was vengeful, but also too lazy to haunt anyone.” She shoved an oxygen mask under Terry’s nose. Terry breathed in the stream of air and earned a respite from his aching skull. “I’m guessing there’s a gas leak in there. Good thing you didn’t light a match.”
Time to talk About the “Sixth Sense”… Kinda
Happy (belated) Halloween everyone! We’re gathered here today to discuss part of the mystical phenomenon of “seeing the unseen,” or the “call from beyond.” Grab your charcuterie crystal or whatnot and join me in calling the spirits from beyond!
…Okay, fine. I lied about the crystals. But for a humble $40, I can certainly provide you with some “fine powder” to give you that experience!
(For legal purposes, this is a joke! The only fine powder I have on me is powdered sugar.)
Yes, friends! The time has come to delve into the science of hallucinations! This is strangely not a common topic to come up in fiction, as most things we would consider “hallucinations” are very much not in a fantasy/scifi world. But even a false haunting can be as horrifying as a real one!
(Once again, for legal purposes, I must remind you all that this is not a “how to” blog. Please don’t actually do any of the substances that will be listed here… or if you do, don’t do it because of the blog!)
What We’re Not Discussing in This Post
I’m not really interested in talking about medical conditions that may lead to hallucinations, mainly due to time. This includes schizophrenia, Parkinsons, and even bi-polar disorder. The post covering those causes of hallucination will require more time and sensitivity in order to write a full-on post.
Instead, this post is dedicated to covering hallucinations that any character can stumble into based on the environment/situation. Perhaps they accidentally ate the wrong mushroom, drank the wrong drink, or breathd in too much strange gas.
So, yep! We’ree going to focus on drugs instead!
(And some injuries, but that wasn’t as funny to type.)
What Are Hallucinations?
Hallucinations are when your brain interprets a signal from one of your senses—smell, taste, touch, sight, hearing— that isn’t there. The “external stimulus,” or the thing in the outside world that you’d feel, see, taste, etc, does not exist.
And the “doesn’t exist” part is really important. There are situations where you may misinterpret what you see, hear, smell, etc, but that’s not a hallucination. The sensation of bugs crawling on you, the sound of voices echoing in your ears, that kind of “fun” experiences. Another important feature of hallucinations is that they are involuntary.
Now, what occurs in the brain on a neuronal level is still relatively unknown. Many of the drugs I talk about below have a lot of hypotheses on how they work, but no definitive mechanism. A study back in 2019 did study the part of the brain that processes vision in mice while they took hallucinogenic drugs; they found that the drugs caused a reduction in neuron activity in that region. I also found this review here that talks about most studies done on brain activity during hallucinations don’t really overlap on what they found. The authors believe this is due to 1) small sample size and 2) the difficult nature of trying to capture in-progress hallucinations that you can’t really plan for. The studies find that patient brains show increased activity, but as to where that activity is located is all over the place, each study finding a different location of activity.
Excitingly, this area of research is ripe for innovation and exploration!
Here’s the thing: I’ve never seen a work of fiction use hallucinations properly, especially hallucinations caused by the environment. I think “Nona the Ninth” came close, but it was the age old “is it schizophrenia or is it a ghost” plot that we’ve seen before and the execution was ultimately underwhelming. A Professor Layton game has also had an entire plot revolved around gas-induced hallucinations, but as much as I love those games, I must admit that it felt like a deus ex machina with that plot reveal. What do you mean all of these hijinks happened because “the characters were high?”
Maybe an environment-related hallucination is not ideal for an entire plot (at least from what I’ve been exposed to), but for one intense scene? Oh, so much potential!
(As usual, let me know if you know of any good book that does this exceptionally well and I’ll read it!)
Time to Talk About Drugs and Poisons!
Many poisons act as neurotransmitters (molecules that latch onto your neurons for signaling), meaning they can stimulate your brain in unexpected ways when you’re exposed to them. We call these types of poisons or drugs hallucinogens. We can’t talk about them all, but we can name a few key ones!
One notable example is the fungus Ergot, or Claviceps purpurea, produces alkaloids that, among other horrible symptoms, can stimulate one’s neurons after digestion and cause hallucinations. Long term poisoning from these fungi is called “ergotism.” It’s so well studied, it even has its own Wikipedia page! Concentrate the alkaloids from Ergots, and you have the precursors to LSD, otherwise known as “acid,” a drug well-known for its visual hallucinations.
What about weed? Well, this article here states that marijuana can in fact cause hallucinations after prolonged use, and those with Parkinson’s Disease were more likely to develop hallucinations after medical marijuana use. Weed use has also been associated with hallucinations. A 2009 Australian study estimates that up ~9% of adolescents experience hallucinations, defined by statements like (and this is taken directly from the article), “I hear voices when I am alone telling me to do things.” Those taking weed were found to be almost 4 times more likely to experience hallucinations. Does that mean the weed caused the hallucinations, or that those who experienced hallucinations were more likely to self-medicate with weed? I couldn’t tell from the paper, honestly.
And then there are magic mushrooms, which produce the molecule Psilocybin. How psilocybin works on the molecular level, no one really knows for sure. However, scientists believe that it changes how serotonin (the “happy” molecule) interacts with your neurons.. Fun fact: along with providing hallucinations, psilocybin also has the potential of being used medically to treat depression.
And then there’s nitrous oxide, also known as “laughing gas.” It shouldn’t be a surprise that a widely used anesthetic that makes patients euphoric can also be a hallucinogenic when abused. Breathing in this gas can cause hallucinations, though it is worth noting that not every patient experienced these as symptoms in the linked article. According to its Wikipedia article, British medical students used to have “laughing gas parties,” which is a wild concept.
What about carbon monoxide poisoning? Carbon monoxide isn’t a poison that stimulates your neurons… but it certainly can make you lose your bearings and make you see things. See, the molecule carbon monoxide binds to the iron in your blood better than oxygen does. Thus, it outcompetes the oxygen in your blood. This means that oxygen can’t get to where it’s needed, including your brain. This can cause headaches, nausea, and of course, even hallucinations. And what’s worse is that carbon monoxide is scentless, which means you won’t realize you’re breathing in a poison until it’s too late. I saw a few articles claiming that carbon monoxide poisoning was the reason for many “hauntings,” but I wasn’t impressed with the evidence they provided. It does make sense, though; when you lose oxygen, you become a tad loopy.
The Toxin List Goes On
I’m honestly concerned about my search history right now, as there’s an uncomfortable list of “hallucinogens” being looked up on both my general and pubmed online searches. I may be on an FBI list after this post. But regardless, the list is quite impressive and certainly work a deep dive if you have the time!
What About Injuries?
I remember being told back in my wilderness first responder training that things like heat stroke can cause hallucinations. However, that training was over ten years ago at this point, and this isn’t mentioned in my training books. I tried diving into the trenches of the web, but I wasn’t happy with the literature that I found (which may just be due to how I’m looking for this info, not that good research hasn’t been done). What do we do if I can’t find great articles? We turn to the experts, specifically my two physician parents (hi mom and dad!).
We spoke about what could cause hallucinations, and generally, anything that causes electrolyte imbalances or low blood flow to the brain can trigger hallucinations. This includes dehydration, extreme hypo/hyperthermia, head injuries, and partial complex seizures. Much like the situation with carbon monoxide poisoning, if we starve the brain of key “ingredients” (blood, oxygen, electrolytes, etc), the likelihood of patients feeling, seeing, or hearing things increases.
Unique Ideas for Fiction
Say we do have a character who’s experiencing a hallucination (let’s say they breathed in some toxins): why must we focus on visual hallucinations? I know we’re visual creatures, but let’s shake things up! Go for the other senses!
Let them smell blood that doesn’t exist.
Let them taste salt in their mouth for not reason.
Let them hear water filling the room and have them panic to find an escape, only for the water to have never existed.
Or have them hear footsteps chasing after them.
And then when the character comes too, they may have to piece together clues of a mystery based on what they experienced, but question everything they saw. Did they actually hear the butler behind the curtain before the crime? Or was that caused by the carbon monoxide leak?
I don’t think these hallucinations need to be constant throughout the story, but if you’re looking to disorient your characters, these are juicy ideas!
Takeaways
There will be a second part to this, as stated above! Don’t know when, yet, but it’ll come!
Anyhoo, enjoy the post-Halloween blog! Onto November!
(And no, I’m not saying “happy holidays” yet. Thanksgiving hasn’t come around. No Christmas songs until November 29.)