Sleep deprivation can bring on seizures in those with a predisposition for them. Seizures can be fatal.
That's me (myoclonic epilepsy)...That's why have to be very careful. My mind is as stable as anyone else's; so I think. It's just that the synapses are a little froggy. Meds are a good thing. My condition is very mild so I would have to limit my awake time w/o meds to about 36-48 hours.