I wish there was more information out there regarding this sort of topic. I had my JPouch surgery almost 20 years ago, and have struggled with depression ever since. I am sure there is some sort of genetic pre-disposition, but I would have to believe that removing the organ that produces 90% of the body's serotonin would be problematic in this regard. I wish someone would have mentioned that all those years ago.
To this day, I rarely, if ever, find information/articles that focus on this.