Janskeet said:
In ROTS, he turns from being a pretty typical human being into a sick, twisted, sadistic, madman within a couple of days, perhaps even hours.

Days? Hours? Try within a couple of seconds, perhaps even minutes.

Now I agree with DarkFather and Confused Matthew. Anakin was a pretty twisted individual from AOTC onward. He was depicted as a creepy obsessive stalker type in his expressions of love for Pandabear, and when he killed a whole villiage of Tuskens, it only confirmed our suspictions that this guy not only needed some professional help, but he also needed to be locked up.

However his transition from that strange twisted freak whom everyone strangely seemed to love so much and seemed happy to accept despite of his severe issues, to the guy who goes around killing halflings and choking his wife to death was painfully abrupt. There is nothing there to indicate the passage of hours or days. In the course of a few minutes, "Palpatine, he is the Sith Lord. We've got to stop him." to "To take that Shaft!" to "What have I done?" to "I pledge myself to you." to "Alright, if it must be done, then it must be done. So, where are these small kids you need me to murder?"