I found that most of my secondaries addressed different questions than the original personal statement. I tried to elaborate some on the original theme of my personal statement, but I didn't use it all over again.
The exception is that a couple of the allopathic schools I applied to actually requested a cut/paste of my original personal statement for the secondary. I can only assume that they use it as a way of getting some idea about you before your entire file is complete from AMCAS.
Though I was tired of writing essays, I did appreciate that VCOM asked some specific questions that allowed me to address things that I never considered putting in my personal statement, but I believe showed more depth and thought than most other secondary essays.
Good luck.
Will~