Denethor's madness.

[Boromir88]

It's clear in the books one of the main contributing factors to Denethor's madness was the palantir, and literally losing his mind to Sauron. The movies stay away from this, so what factors in the movie does contribute to Denethor's madness. I haven't seen the appendices so if someone has, maybe there's some helpful info in there.

Was it simply the loss of his son Boromir? Or in TTT EE did it appear there was something whacky about Denethor, besides the fact that he was a mean father to Faramir? Perhaps it was also the thinking that Faramir was dead, and he had no heir, his line had "ended." Therefor he saw no need in resisting Sauron anymore? I don't know, just some ideas, since Jackson stayed away from the palantir, I wanted to see what was in the movie to try to show Denethor's madness. Or, whether Jackson just showed Denethor being a crazy guy from the very beginning.