by Dale Williams
It is actually multiple questions:
1) Will a person who is sleep deprived know for certain that they are?
Yes, the person that is sleep deprived will know for sure. Here is my page on the effects of sleep deprivation.
2) Can a person who is sleep deprived feel seemingly alright in through the course of a day? No they won’t. They will have feelings of tiredness. They will eat more. They get more depressed etc.
3) Can a person who is sleep deprived, who was feeling alright, suddenly have a 'crash' and their body shut down?
By crash, do you mean collapsing? if that is what you mean, yes it can happen. The sleep deprivation must have been going on for weeks and probably the person is not totally healthy or has some other medical condition.
4) Can a person who is sleep deprived be responsible for this sudden 'crash'?
People get sleep deprived for different reasons, the crash is not necessarily the person fault.
I hope I have been able to answer your questions. If you have more questions just leave a comment on this one and I will get back to you.