Simpson was acquitted on criminal charges in the slaying of his ex-wife, Nicole Brown Simpson, and her friend, Ron Goldman, but his book offers a supposedly fictionalized account of how the killings might have happened if Simpson "did it."
"I believe that O.J. was not smart enough to maintain the separation between the hypothetical and getting caught up in the interview process. And it's interesting to me, psychologically, that there is a shift in his tone, his demeanor, his language, everything, when he gets into those details," McGraw said in a statement.
McGraw invited Fred Goldman and Kim Goldman -- Ron Goldman's father and sister -- to confront the book's ghost writer, Pablo Fenjves, for the first time, in the "Dr. Phil" show to air Monday.
The Goldmans explain why they allowed the book's publication, while Fenjevs defends his reason for wanting to write it and reveals what he said Simpson asked him to leave out.
McGraw will also point to the psychological revelations he believes Simpson unknowingly left in the book, which McGraw said are tantamount to a written confession to the crime.