It is the same as if you were on the ground, however the blood pressure may be lower after you return from space, because you have less blood volume. Sure they can, however, your taste can be different. Due to fluid shifting to the head, your nose may be stuffed up, therefore you may not be able to smell. Without gravity, your stomach may feel full in space. For example, like eating lying flat on earth.
Digestion is slower in space due to a decrease in digestive tract movement.
We monitor the astronauts for the mood they are in while they are in space. The astronauts can email their families and friends, to help avoid any potential depression. There has been no insanity or severe depression in space. I was searching the web for information on a drug called melatonin used for sleep problems. I found a 1998 NASA Shuttle Web report about a study that was to be done on the Shuttle to test this drug.