Methamphetamine, more commonly referred to at the time by the trade name Benzedrine, was officially issued to troops on both sides in World War II, with, as I understand it, the most extensive use being in American units. The main object being to keep people awake and alert and so forth, for a crucial limited period.

I've never heard that it's any use for stopping people being scared. Might help you keep going even if you were scared, but that's a different thing.