An excellent objective description of a single case is furnished by the “Gentleman” in “Hamlet” who announces the frenzy of Ophelia:
“She speaks much of her father; says she hears
There’s tricks i’ the world, and hems and beats her heart;
Spurns enviously at straws; speaks things in doubt,
That carry but half sense; her speech is nothing,
Yet the unshaped use of it doth move
The hearers to collection; they aim at it,
And botch the words up fit to their own thoughts;
Which as her winks and nods and gestures yield them
Indeed would make one think there might be thought,