A friend in high school wanted to try doing 100 hours, no caffeine, no stimulants, just pure willpower to see if he could do it.
He was actually pretty good around 48 hours, he didn't look like he was suffering at all.
After that, he wanted at least someone with him to keep him on the straight and narrow. Whoever was with him could yell, slap him in the face, throw some water in his face, whatever we had to do to keep him awake. But he was still doing really well. He was a little slow on the uptake, and you could see him catching himself nodding off, but he still wanted in.
At hour 85 or something, it was a complete psychotic break. He was talking to people that weren't there, he'd start laughing like he was insane, then just start crying. Slapping him awake worked physically, he "woke up", but it didn't register with him. I existed just as much to him as whoever or whatever he thought was in the room with us.
So I had to stop and let him sleep. He made it 90-something hours, and he was a little pissed that I didn't keep him going until 100, but I was also babysitting him from walking off balconies and stabbing himself with a pen, so I wasn't up for another half day of that.