Inflammation in the gut is encoded by neurons in the brain
For me, the thing that sucks most about IBS is the medication. The link between mind/body/pain/inflammation is pretty obvious when you start taking strong anti-inflammatory drugs, at least for me!  Evidently, everyone in my family tree responds really poorly to steroids and other anti-inflammatory drugs - a relative of mine committed suicide after taking steroids for IBS with absolutely no evident mental problems before treatment, leaving behind his young family.   Personally, I'd rather die early from my gut diseases than go back on anti-inflammatory drugs, even the modern biologic ones that supposedly have no side-effects.  There's just no way to target inflammation with drugs without severely impacting the brain (at least with me and my family's biology).