How did they have a baseline of who was "depressed" or "anxious" beforehand. If someone had sought help for these conditions, getting horrible diarrhea could make them more freaked out, something ELSE!, not the freaking out "causing" the continued affliction. I maintain that it's the flora and fauna in there that starts the symptoms, then the desperation and depression follows, and maybe causes a chemical soup where more "bad" flora and fauna develop, on and on. They are learning so much (about time!) about how the brain, immune system, and gut are connected. I hope some of this results in a simple approach--along the lines of the antibiotics for ulcers gambit.