The Russian Sleep Experiment (Part 1 – The Setup & First Signs)

Russian researchers in the late 1940s kept five people awake for fifteen days using an experimental gas-based stimulant. They were kept in a sealed environment to carefully monitor their oxygen intake so the gas didn't kill them, since it was toxic in high concentrations. This was before closed circuit cameras, so they had only microphones and five-inch-thick glass porthole-sized windows into the chamber to monitor them. The chamber was stocked with books and cots to sleep on (but no bedding), as well as running water, a toilet, and enough dried food to last all five for over a month.

The test subjects were political prisoners deemed enemies of the state during World War II.

Everything was fine for the first five days; the subjects hardly complained, having been promised (falsely) that they would be freed if they submitted to the test and did not sleep for 30 days. Their conversations and activities were monitored, and it was noted that they continued to talk about increasingly traumatic incidents in their past. The general tone of their conversations took on a darker aspect after the four day mark.