I have to wonder about the "Captain Queeg" factor, though. If a candidate really does have some sort of neurosis or disorder, it would be a good idea not to elect him. The long campaigns we have may do something to weed out candidates who have some mental problems -- though some disorders may actually work to a politician's advantage, at least until they get elected.
Some conditions, though, may not show up until a crisis happens. The idea that you can separate out those the determined from overly rigid, or the easy-going from the spinless before hand is a delusion, since those who write such long-distance analyses are usually influenced more by their own prejudices than by actual objective data.
Actually, there is something to be said for having a psychoneurosis in a specific occupation.
For instance, would you really want a LEO who wasn't at least a little paranoid? ("Oh,don't worry . . .be happy"); how about a surgeon who wasn't somewhat o/c? (This scalpel was on the OR floor less than 5 seconds.)
As for politicians, need I say more?