To really fully understand this seemingly unlikely conundrum, it's a good idea to search for similar situations in other drugs which share the same characteristics of Ketamine. Ketamine used to be my absolute drug of choice throughout the last year or so. I too have suffered from grand mal seizures on two separate occasions, both occurring after extended binges with Ketamine. In these binges, I would typically snort anywhere from 350-750mg of Ketamine in a day, over the course of 3 or 4 days, usually with little to no sleep and without proper nutrition/eating. The thing that sticks with me still today, and has led me to research this phenomena is that the seizures didn't occur during the intoxication, but rather 5-8 hours after reaching sobriety at the end of the binge. The Ketamine was 100% uncut, because I was buying sealed vials from a vet source. After reading up some, I came to find that the most reasonable explanation for this was withdrawal from Ketamine, and extended use of high-doses of ketamine on multiple occasions within a small time-frame. Keep in mind these binges happened frequently, cuz I just couldn't get enough of the stuff, and the supply was endless. So let's break this down.
We know that Ketamine is a dissociative drug. Just from this information, we can deduce that Ketamine may very well cause seizures within it's very usage. Why? The answer lies within two relatives of Ketamine: DXM and PCP.
a) DXM: Drug Forums
-From this article, they cite DXM's potential as an anti-convulsant (like ketamine) in rats. However, they found that in high doses it becomes a pro-convulsant. Also, they found that seizures were reported when moderate doses (300mg) were delivered in two sessions apart from eachother.
b) PCP: Erowid
-Even when simply researching the effects of PCP, seizures are noted as a side-effect in high doses.
So now, to further strengthen this hypothesis, let's dig a little deeper. What do all three of these compounds have in common? They're dissociatives, yes, but more importantly, they are all NMDA receptor antagonists. This is a very crucial aspect to acknowledge. Upon quick research you'll find that there are other NMDA receptor antagonists also known to cause seizures, such as MK-801, Tiletamine, and Methadone. Methadone was the big eye opener for me on this quest, because I know nurses/doctors at methadone clinics will strongly advise against suddenly stopping methadone treatment because it is very possible that seizures will occur. The reason this sticks out is because methadone does not produce dissociating effects, but instead, opiate-like effects. One does not have seizures from actual opiate withdrawals, but methadone does not act on the brain in the same manner as opiates. ITS A NMDA RECEPTOR ANTAGONIST. So now we can draw the conclusion that ketamine and other dissociative drugs don't necessarily promote seizure-like activity because of their effects, but because of how they work on the brain.
That's the summary of my firm stance on the subject. If you need more convincing, here's a few more angles for you:
1) Think of it this way, opiates are pain relievers. However, over extended use of high doses of opiates, you'll find that when you come off of opiates, you are actually in pain if you weren't before, or in worse pain if you were. Apply this to Ketamine. Ketamine is an anti-convulsant. However, over extended use of high doses of Ketamine, you actually exhibit convulsions if you didn't before, or worse if you have. Doesn't that kinda make sense?
2) Drugs are not the only factor in the occurrence of seizures, even in instances where there use leads to seizures. Remember that you and your friends have used Ketamine on multiple occasions without this happening. Other factors such as: Stress, Sleep Deprivation, Malnutrition, and contraindications from other combinations of chemical substances play a key role in the stability of your seizure threshold. When I had my seizures, I had been up for about 2 days, using minimum doses of 125-150mg of Ketamine at a time. The second time I had also been using Methamphetamine and alcohol.
3) The dissociating effects of Ketamine are caused by the brain blocking singles sent from your body to your brain. You can still output messages from your brain to your body, but your brain will not receive the response from the body. This explains the numbing effect of Ketamine on the body, as well as the lack of motor coordination, the stiffness of the body, the the lack of association with your overall body's existence. It kind of just seems right to think that seizures could result from a drug which tampers with the brain-body communication so heavily.
Overall, I would definitely suggest to your friends to heavily consider this information in relation to Ketamine. After my first seizure I had no intention of quitting my use. I definitely cut back tremendously, but it took me a second seizure to really understand how powerful that drug is in the body. I have since used Ketamine one time, snorting 2-200mg lines, and experienced no ill effects. However, in this situation I spent alot of time thinking about how stable I was with nutrition, sleep, and stress, and knew that I should definitely not even touch the drug but once every 2-4 weeks if anything. I would really just altogether stop use, because my mental/physical health isn't worth a drug when the threat is that heavy. Remember seizures cause brain damage. You never know what seizures gonna turn you retarded. Be careful, and I hope this has helped you!