Lana went crazy? She didn't go crazy she left and dumped Clark via video. Also they didn't kill Whitney, he left to join the marines. Eric Johnson stated that he was pleased with his exit from the series.
When I say they "killed Whitney", I mean that TPTB killed off his character (even though they say he goes to the Marines). But then in season 2, we find out that Whitney died oversees, but they bring him back anyway as a Freak of the Week.
And Lana definitely goes crazy, she starts that Isis foundation and starts being all sneaky. The video thing was really cheap.