There is no way to make sure that they wont go crazy on mars.
What I did not describe yet is that the Mars population gets expanded by a new crew consisting of four people every 2 years.
Also, some interesting points. How will they imply laws on another planet? (Think about weed legalization, how trippy would it be to be extremely high on Mars!) How will they prevent the settlement meeting failure or insanity? Some ethical FAQ can be found
here. It certainly does not cover what you would expect. Then again of all those people that signed up, or at least a percentage of them thought it over well enough to make a lifechanging decision.
I decided to picture it in my mind a little more and it almost seems like a surrealistic game scenario, yeah?
Like the game Fallout 3, where you meet the lands of where you used to live but totally destroyed by nuclear war. It comes very close to the martian landscape to say at least. Only there will be no trees, no buildings, nothing but dust.