There are drugs for some of those things...
1) Barbiturates induce a hypnotic state that has widely been reported to improve subjects ability to recall details. Published work on human subjects more or less dried up in the early 70s for ethical grounds (cf. http://ist-socrates.berkeley.edu/~kihlstrm/exhumed.htm "There is, unfortunately, a virtual lack of controlled clinical studies on the accuracy of hypnotically refreshed memories."), but I bet the military have classified knowledge. Also, there's been quite a bit of published work on recall under barbiturates in dogs and rats.
2) So, you wake up with a hangover, a blackout, some bruises, and an attractive stranger in your bed. What do you assume?
3) There are drugs to suppress memories. Barbiturates, again, make it hard to recall details of the trance. Also, see http://mbldownloads.com/0205CNS_Pitman.pdf
4) Barbiturates, yet again, are well-documented to improve compliance, though at the expense of an apparent willingness to cause you to believe what you think will please the interrogator rather than what you would normally believe to be true.