This may be a long shot, but do you know if they have switched her to the generic for
Zoloft? I have been on Zoloft for many years, and noticed in the past year or so it didn't seem to be as effective. I finally figured out that it was about the time that I started getting the generic that things weren't quite the same. So, I talked to my doctor, and she said she had had other patients have different reactions to the generic. I also asked another doctor I see, and he said that some people, like me, tend to be very sensitive to fillers and formulations and that the generics do not always have the same delivery system as the name brand, which could account for the different effect I had.
I know it may sound ridiculous, but when she re-wrote the prescription for the name brand, within a month I was back to myself. This may not have anything to do with your wife's issue, but it might be worth inquiring about.
-T