I think they mean Red John is VanPelt struck by multiple personality disorder. Which means she would change her identity and behavior patterns unknowingly because multiple personality accompanies memory loss so that one personality would not recall anything done by the other. Basically it's two personalities taking over the same body. in this case Grace and Red John are two personalities of the same person!
I can see why you say it but I have doubts specially because of the time frame! VanPelt looks to be in her late twenties when Red John's career started in 1998!
