I haven't - yet. But, I've mostly dealt with my past trauma. It's current (and future) issues that I need help with.
Many of us use food as a coping mechanism for emotional pain - the same way an alcoholic uses alcohol, or a drug addict uses drugs.
If you take away a person's drug of choice - ours often being food - then it stands to reason that we will have to deal with the issues that we've been masking with the use of food. Well, we either have to deal with the issues or we get to look forward to transfer addiction (or regaining our weight in a year).
I knew that I had issues with food and that I used food as a coping mechanism. So, about 2 months before surgery, I started therapy. If you have unresolved trauma that is coming up (or that you're worried will come up) I would suggest speaking to a counselor.
The surgeon works on our stomach - not our brain. And if our reason for overeating was mental, then the surgery will only help us in the short term. Eventually, our tummies will heal and we'll be able to eat large amounts of food again. And if we aren't careful, and we make poor choices, then we will regain our weight. We really need to be taking advantage of this first year after surgery, to change our relationship with food.