Having just come off of a two week intense military field training exercise, I had a personal experience that is relevant to a SHTF and WROL situation.
During most of the FTX, we were going for 24-36 hours consistently without sleep. Then when we would sleep, it was very little (3-4 hrs at most) and very uncomfortable (sitting up or leaning over or even standing up). However, there was a period that we were awake and moving in vehicles for over 40 hours. At about 0200 in the morning, I was using night vision monocular in order to help our vehicle's driver move in and around the desert terrain. All of a sudden I started noticing human faces in the sand. Realizing that many shapes and forms can be seen in nature, I initially thought nothing of it. However, very quickly I noticed that everywhere I looked I was seeing faces everywhere. The exhaustion hallucinations had started!
Looking through NVDs many natural objects take different colors and shapes than what they normally exhibit. There is a desert plant that takes the form and color of large boulders when viewed through NVDs. What was the next kicker was that these boulders began to morph and change shape into unnatural mythological creatures! The next stage of hallucinations was occurring. Finally, these same creatures just started to come up out of the ground and moving all over the place.
There are many causes of hallucinations, however, for this discussion, we are looking at the issue of hallucinations caused by exhaustion. Going for long periods of time with little to no sleep are a common stress item with many military training exercises. Knowing your body's and mind's limitations helps you plan for future operations. Consider this with your own preps in mind. You must be able to know when your mind and body hit the wall and it possible, move beyond it.
I knew that what I was experiencing was not real. Therefore, I was able to push through it and keep going. But how many of us know people who would not be able to move past those kind of experiences?
Add to this poor food intake, close quarters, poor hygiene, inadequate bathroom facilities, and the list goes on. Knowing your limits, knowing the limits of your family, extended family, and other group members will aid you in planning the every day activities of your NPT or retreat location. Most people can go without a single nights sleep and recover fairly quickly. However, when there is no real end in sight, and the sleep cycle is completely broken, there will be noticeable changes in the attitudes and capabilities of everyone involved.