LFG

Okay, so.... honestly, I don't really see this exact dynamic in the book.

Yes, Alia is completely devoted to Paul and the empire and her role in it (she doesn't know anything else) but I've never really seen her as obsessed with Paul himself. She has an oppositional relationship with Irulan mostly because she dislikes and doesn't trust her, and is close friends with Chani, Paul's wife, with whom Paul is kind of obsessed. She's not jealous and she doesn't really try to monopolise his time or attention despite the fact that she might want more of it. I don't see her attitude toward him as anything that's emotionally extreme in that overt of a way (all of that kinda lies beneath the surface, the same way as most emotions in the original books)

If anything, I think Paul's presence is grounding for her. He is, by the end of Messiah, actively suicidal, depressed and totally hopeless, but all the way, he is mostly calm and steady. He is a rock for people because they need him to be, and I think Alia feels that too. It's only after he, her only real support network (and Chani too tbf), is dead that she starts the spiral that she's caught in by CoD. He's also the one who can understand her and I think that was a great comfort, while he was still around. It's not his presence that drives her crazy, but his absence.

From the sword training scene and the spice overdose scene in Messiah, we know she already had these self-destructive impulses, but they only take over once she loses the only person who could understand her, who helped her keep her feet on the ground. I would call their relationship a lot of things, it's certainly intense and complex, but obsession isn't the word that comes to my mind to describe how she feels about him, or it certainly wouldn't be the only one, at any rate.