Good Morning and welcome to the Anxiety forum,WE have another thread running re Lexapro currently so do take a peek at the info in that thread.
While stress doesn't cause UC, when someone is under stress, the body gears up for a fight-or-flight response by secreting certain hormones, including adrenalin, as well as molecules called cytokines. They stimulate the immune system, which triggers inflammation. In people whose ulcerative colitis is in remission, this sets the stage for the return of their symptoms, known as a flare-up. My husband is a Chronie of 38 years and I can definitely see the correlation between a rise in his stress level and his Crohn's flares.
IBS can also be affected by a persons stress level. Please remember these are simply my own thoughts.
My husband's Dr. started him on an AD for his anxiety however hubby did not like the way it made him feel and only took a couple of pills. I wish you luck with starting your new med and remember the side effects that come with starting the new med may last from 6-8 weeks before you experience the full therapeutic effect of the medication. You should start to feel some improvement within a couple of weeks.
Kindly,
Kitt