This is more like the misconception of the previous century (20th). As elaborated by Dr. Miller, people in the 19th century readily attributed mental problems to gut function, if sometimes in hilarious ways. But by the 20th century, a more top-down view of the relationship between gut and brain dominated. Personality (especially “neurotic” personality) and stress were blamed for gastric and duodenal ulcers (Alp 1970, Jass 1994, Piper 1993). Eventually it was revealed in the 1990s that gastric ulcers are triggered by overgrowth of Helicobacter pylori (Malfertheiner, 2023). But even after that, the emotions of people with other gut disorders, especially the functional bowel disorders such as IBS, were still being blamed for the gut symptoms.
This was dramatically illustrated to me around 1984, when I was a graduate student at UCLA. I attended a Grand Rounds lecture given by the Eating Disorders Center and (I think) the Department of Gastroenterology. For this presentation, they interviewed a very, very thin (nearly skeletal) woman. She presented as highly strung, anxious, and a little defensive. She lived with her ailing grandfather, whom she supported financially and as a care-giver. Money was tight. She was referred to the Eating Disorders (ED) Clinic because she had lost so much weight, and said that she could only eat “Mrs. See’s chocolate” (the good stuff in those days), due to excessive gut pain if she ate anything else. As you might expect, this explanation was not believed. She bounced around psychiatrists before one referred her to UCLA’s ED clinic. When interviewed, she stated very clearly that she wanted to eat but couldn’t. Since she reported severe gut pain, the practitioners at the ED clinic thought she should be “scoped” to see if there was anything wrong with her gut to explain her pain. When that was done, it was found that she had severe inflammation extending from her top of her esophagus to her rectum. She had severe Crohn’s disease. What shocked me though, was how long she had gone before her story was taken seriously. She presented as neurotic, so that must be her problem, right?
We have come a long ways in understanding gut-brain interactions since then, but advice about dealing with mood symptoms for people with gut problems is still top-down: the emphasis is managing stress, but much less on dietary improvements that could alleviate interoceptive anxiety.