A case report from 1974 says that massive LSD overdoses can cause bleeding and hyperthermia, symptoms which could potentially be fatal without medical attention (but, in this case, medical attention was received and all survived)
Wow, I wonder if they spoke about it publicly after the fact. There aren't a lot of stories like this. Did they remember the experience? Was it really a coma or some out of body experience? It would be interesting to see how differently their lives went versus their peers.
What hype? I think it is very likely that a sufficiently high dose of just about any drug, LSD included, will kill someone. If no one has died yet, that just means no one has ever taken a big enough overdose.
We know the LD50 of LSD in rabbits, rats and mice [1]. Surely, there exists a human LD50 as well, it is just that hopefully nobody will ever be evil enough to do the necessary human experiments to determine it. (That's true for all drugs – just because we can't ethically discover the human LD50 doesn't mean one doesn't exist.)
What's the biggest overdose anybody has ever taken? This case report is the biggest one I know about. And yet, they each only consumed "two lines" of 3mm by 4mm by 30 mm, which is less than a gram, administered nasally. They were hospitalised. Would they have lived without medical attention? We don't know, but quite possibly not. And surely it would have been physically possible to take an even bigger overdose than that. How do we know an even more massive overdose would not have been fatal?
People rarely take LSD intravenously. I think a fatal overdose of LSD would most easily achieved with intravenous administration. That's what the animal study LD50s are calculated based on.
Unless you are trying to commit suicide or murder, you wouldn't do it. And if you are trying to do either, there are far more practical methods than massive LSD overdoses.
EDIT: I deleted my back of the envelope calculations about how much the people took in mg/kg. I don't have confidence I'm doing it right so better not to.
i once took 82 hits of acid. ahh, to be 17 years old and think you're invincible again.
each hit was a gellcap with about 4 hits like blotter paper. this was at an outdoor rave-festival.
i was curled up in a ball in a tent for 2 days. fully immersive hallucinations. the good thing is when you are so incapacitated, you cant get up and move around to hurt yourself and others. i had sitters watching me and feeding me water.
nothing happened. i slowly returned to sober consciousness with zero bad physical side effects. except dissappointment that i had missed the entire rave.
that was the greatest spiritual experience i have ever had. none of the hallucinations were scary or negative, likely because the setting was outdoors on a rural camp ground in nature. i was talking to the Sun. and the blades of grass. and they talked back. i felt an indescribable oneness with all living beings and a realization that all life is sentient. meaning that our "human consciousness" model is just a tiny sliver of the full spectrum of "living consciousness", only we dont see the greater consciousness while we go about our daily lives trapped inside our limited minds. as an analogy, think of human consciousness like a language--C or assembly. then Universal Consciousness is like Leibnitz's mythical Perfect Language which simultaneously describes and creates our Monadic world.
decades later, that experience is still one of my happiest and i can remember it more vividly than more recent milestone events.
i understand why Steve Jobs said his first time tripping was his #2 greatest life experience.
if you ever have the opportunity to take 360 hits of acid, i recommend you go for it. you will see God and it will permanently reprogram your brain.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1129381/