K-Holing: Why Ketamine Causes Wild Hallucinations

A simple explainer for why doing one too many lines of ket can turn your reality inside out – and what you can do to alleviate it.
Girl with 'I Want Ketamine' written on her back at a music festival
Photo: Everynight Images / Alamy Stock Photo

“Ketamine? More like regretamine! Just one hit of that stuff and it’s death for you!” Words to that effect formed the basis of the drugs ed advice that I, and most other humans educated in the last 100 years, experienced in their teenage years at school. The one major flaw of pro-abstinence though, is that eventually all people grow old enough to make decisions for themselves and discover that doing a line at a party doesn’t result in instant death.


Sadly for me – partly due to the fact that I am a very anxious person with a fear of death – it worked and I’ve never taken any drugs in my life! (Editor’s note: Sure.) But it hasn’t curtailed my curiosity about ketamine, and one of its most confusing and chaotic potential side effects: the K-hole – the point at which snorting bumps of ket stops resulting in slightly trippy, gentle numbness and spins out into wildly strange, immersive hallucinations and full-body paralysis.

To the rest of the world, you’re a drooling, catatonic mess. Inside, according to Dr David Belin, a behavioural science lecturer at the University of Cambridge, “you’re disrupting the activating system of the brain – the glutamate system – which acts as the ‘on’ signal throughout [your brain]. Taking too much ketamine ends up with your system being too weak, and therefore, you start to lose consciousness.”

“There was one time I did it and I thought I was dead,” Jacob Hawley, a stand-up comedian and host of the new BBC Sounds podcast On Drugs, says of one of his strangest K-holes. “On the outside, I was laying on a dancefloor in a nightclub in a very small town, screaming for my dad, and had to be carried by all the bouncers. But in my head, I was just very much at peace with the fact that I was dead.”

Jacob distinguishes between the dissociative state and sheer weirdness of a K-hole from your garden variety psychedelic trip: “In terms of the tripping, there are visual effects where everything goes very blurry and colours go a bit strange. But it’s only when you do enough to go into a K-hole that you really start having mad visions.”


To find out why too much ket can literally turn your reality inside out, I turned to Professor David Nutt, a neuropsychopharmacologist at Imperial College London and the chair of Drug Science, an independent scientific body on drugs in the UK.

“If you take a sedative anaesthetic, like midazolam or propofol, they put you into a state of extreme synchronicity,” explains Nutt. “The brain becomes locked into a rhythmic activity which is very repetitive and you can’t do anything because all the brain activity is working in a very regimented way, so you fall asleep.”

“With ketamine, everything is very fragmented so there’s activity going on but it’s very disorganised. Normal consciousness is a level of activity somewhere between the two. If you’re over-synchronised, you’re deeply asleep. If you’re under-synchronised, you’re in a psychedelic state where you’re seeing and experiencing things differently to what they are.”

This may explain why a K-hole might feel different to, say, an acid trip. “If you imagine an orchestra as an analogy for the brain, LSD takes away the conductor and allows all the different musicians to play their own tune. Different sub-groups can develop within the orchestra, so that would explain the connectivity between sight and sound or taste and sound. With ketamine, it’s almost like the instruments [themselves] would be disorganised.”

If it sounds like it makes for a confusing trip, you’re right! “My mate had a thing where, when he would get towards that tripping and hallucination stage – I think this happens with a lot of people where you go back to the same trip you were having the last time you did ket – and he had a family,” Jacob adds. “Like, within his trip, he had a family. He had this life that he would return to [with] a wife and kids and he’d almost be like ‘I’m back’ and return to this whole other life.”


This might seem incredibly random, it’s not unusual for the brain to ad-lib creatively when you’re on ket. “With ketamine, you’ve taken away the inputs from the eyes and the ears and disrupted them, so your brain is just trying to fill in the missing gaps,” Nutt explains. “Within the 30 odd years that you’ve been seeing things, your brain has worked out a very clear, repetitive, regimented way of making sense of everything.

“Everything you do, see, think and feel has been learnt and practiced and that relies on a neurotransmitter called glutamate. You distract glutamate with ketamine and those processes are distorted.” Essentially, your brain can’t quite process sensory input during a K-hole – but with a little imagination, it can overcompensate and dream up a fake family. Magic!

Is there any way to pull yourself or a mate out of a K-hole after one line too many? Belin has some bad news: “There is no safe way to reverse the effects of ketamine overdose or too high intoxication.” Essentially, you’re gonna have to wait it out or call 999 in case of an emergency. If you’re with a friend, it’s a good idea to stay with them in a safe place and keep talking to them so you know how they’re doing. Make sure they’re sat up – ketamine can cause nausea and you don’t want them to choke on their own vomit lying down.

Most of all, remember to only take it in safe environments with people you trust. Long-term ketamine abuse can thicken the walls of your bladder and cause a deterioration of proper kidney function and ketamine dependency also been linked to psychosis and schizophrenia. So remember to trip safely, and try not to think too much about your brain as a dysfunctional orchestra next time you’re verging on a K-hole.