Paula has recently given an interview in the new issue of OK! Magazine regarding her "medicated" appearance on several TV appearances. Abdul has mentioned that she has been diagnosed with reflex sympathetic dystrophy (RSD), a neurological disorder that causes intense pain.
"It can come and go at any time, but I no longer have the intense nerve pain that is associated with RSD, thank God," Adbul tells the mag. "I have four titanium plates in my neck. I've had 14 surgeries over the years," "I had an operation the same evening as the first season finale of American Idol."
"If I appear exhausted on television, it's because I am!" she says. "I have a lot of sleepless nights because I'm in so much pain. I was taking far more medication on earlier seasons [of Idol], and nobody said anything. I try to say something and I stumble, and that's what people have picked up on. I'm not polished."
I don't know if "exhausted" is the word I would use to describe her appearance, more like hammered. There's a difference between looking tired and slurring your words so much that not even a drunken homeless man can understand you.
Source