Regarding scopolamine, Vice magazine made a documentary about the way it's used in Columbia. It's rather unsettling, but worth watching if you're interested in this kind of stuff.
Scopolamine behind-the-ear patches are readily available with a prescription. It absolutely cures motion sickness, but it also makes you so sleepy that it's almost pointless. Which is why NASA mixes it with a stimulant.
And yes, scopolamine in larger doses is the classic "truth serum" in that it tends to loosen inhibitions. But lots of other drugs do that too.
https://video.vice.com/en_us/video/worlds-scariest-drug-colo...