Bien sur. (Where do you think I've been for the past couple of weeks?) We agree completely that any change in the way an individual manages affect will alter personality. Tomkins stated that we are born with the circuitry for nine innate mechanisms that are responsible for nine distinctly different forms of affect, producing nine different ways of paying attention to a stimulus. Therefore, he suggested, we can think of personality as "the differential magnification of innate affect."
Stated somewhat differently, since we've all got the same palette of affects, and since one of the big jobs leading to maturity is the task of learning to manage those affects, our personality will be a subset of the affect management system each of us learns. Any therapy that allows important shifts in the way an individual manages affect will certainly bring about a change in character structure.
I've commented in many venues that I believe Prozac and the rest of the SSRIs work to change character in many people by reducing the punishment brought by a biological glitch that causes chronic shame. This, too, would conform to the observation Jim and I are making that any treatment that alters the way we handle affect is likely to change personality.