The Hamlet Project

Which done, she took the fruits of my advice
And he, repelled, a short tale to make,
Fell into a sadness, then into a fast,
Thence to a watch, thence into a weakness,
Thence to a lightness, and by this declension,
Into the madness wherein now he raves
And all we mourn for.

Not such a short tale, is it? And a very linear journey to madness.
This is either:
a) a recipe straight from some pedantic text on madness or
b) a made up series of events or actually
c) Hamlet following the madness recipe straight from that same DSM of Denmark.
Because any madness I’ve ever seen never follows this step by step process. It can spring up on you all of a sudden or it can sneak in slowly bit by bit but this list sounds like depression slipping slowly into some sort of listlessness, not at all like madness. I guess I’m wondering if Polonius witnessed these symptoms or if he’s making some big assumptions.