Factual error: While it is true that lithium carbonate can be used to treat depression and other psychiatric disorders, it cannot be administered in gaseous form. It is a very stable salt and only starts to form vapour at 1,310 degress Celcius. Spraying it about as a 'mood stabliser' at that temperature, as Kryten does, is going to kill everyone on the spot.
Suggested correction: Apparently, 3 million years in the future, it can.
What cobblers. You cannot sublimate a stable salt into a gas at room temperature now; you never have been able to, and you will not be able to three million years in the future, either.