The GI-Brain Connection: What Your Stomach Is Telling You That Your Therapist Should Be Asking About
I helped start the GI psychology program at Kaiser Oakland. That experience taught me something that has shaped my clinical thinking ever since: a remarkable number of people sitting in a gastroenterologist’s office do not primarily have a stomach problem. They have a nervous system problem that is expressing itself through the gut. And conversely, a remarkable number of people sitting in a therapist’s office have anxiety, depression, or chronic stress that is being driven, in part, by a GI system that is in distress. The two are not separate. They are the same system, communicating through different channels.
The Gut-Brain Axis Is Not a Metaphor
When we say someone has a “gut feeling,” we are describing something neurologically literal. The enteric nervous system—the network of over 100 million neurons lining your gastrointestinal tract—is sometimes called the second brain. It communicates directly with the central nervous system through the vagus nerve, the longest cranial nerve in the body, which runs from the brainstem to the abdomen. Approximately 90 percent of the signals traveling along the vagus nerve go from the gut to the brain, not the other direction. Your gut is not just receiving instructions from your brain. It is sending them.
This bidirectional communication system means that psychological distress can produce very real GI symptoms—nausea, cramping, diarrhea, constipation, bloating, acid reflux—and that chronic GI dysfunction can produce or worsen anxiety and depression. If you have ever had a presentation the next morning and spent the night in the bathroom, you have experienced this axis in action. If it happens regularly, it is not a coincidence. It is your nervous system talking.
What I Saw in the GI Psychology Clinic
Working in GI psychology, I saw patients who had been through every test available—endoscopies, colonoscopies, imaging, bloodwork—and received the same frustrating answer: everything looks normal. For many of them, the implied message was that their suffering was not real, or that it was “in their head.” Both conclusions are wrong.
Functional GI disorders—conditions like irritable bowel syndrome, functional dyspepsia, and centrally mediated abdominal pain—are not imaginary. They are disorders of gut-brain interaction. The pain, the urgency, the disruption to daily life are genuine and measurable. What is different about these conditions is that the dysfunction is in the signaling between the gut and the brain, not in the tissue itself. And that means the most effective treatment is often psychological, not surgical or pharmacological.
Cognitive behavioral therapy adapted for GI conditions, gut-directed hypnotherapy, and stress management interventions have robust evidence for reducing symptom severity in functional GI disorders—in some studies outperforming medication. This is not because the condition is “just anxiety.” It is because the condition involves the same neural pathways that anxiety uses, and treating those pathways treats the symptoms.
What Your Therapist Should Be Asking
If you are in therapy for anxiety or depression, and your therapist has never asked about your digestion, that is a gap. Chronic GI symptoms are one of the most reliable somatic markers of psychological distress, and they also function as a maintenance factor—meaning the GI discomfort itself generates additional anxiety, which worsens the GI symptoms, which generates more anxiety. It is a feedback loop, and it needs to be addressed as one.
Similarly, if you are seeing a gastroenterologist for chronic symptoms and no one has referred you for psychological assessment, you are getting an incomplete picture. This is not because your symptoms are not real. It is because the system producing them spans two organs—the gut and the brain—and treating only one is like fixing half a circuit.
The Stress-Digestion Connection in High Achievers
In my current practice, I see this pattern constantly in driven professionals. The person who skips meals during the workday and then eats a large dinner while simultaneously answering emails. The person who drinks coffee on an empty stomach to power through mornings and wonders why they have acid reflux by noon. The person whose IBS flares predictably around quarterly reviews, travel, or family visits. These are not coincidences. They are data.
Your GI system responds to how you eat, when you eat, and what psychological state you are in when you eat. Eating while stressed diverts blood flow away from the digestive system toward the muscles and brain—the sympathetic nervous system does not prioritize digestion when it believes you are under threat. Chronic stress alters gut motility, increases intestinal permeability, and disrupts the microbiome. If you are treating your body like a machine that processes fuel, your gut will eventually insist on being treated like an organ that has needs.
What You Can Do
If your stomach has been trying to get your attention, start listening. Eat at regular intervals. Sit down when you eat. Reduce stimulation during meals—put the phone away, close the laptop. Notice what your GI system does in response to specific stressors and treat that information as clinically meaningful.
And if you have been chasing a diagnosis for chronic GI symptoms without resolution, consider that the missing piece may not be another test. It may be a psychologist who understands how the gut and brain talk to each other.
Your stomach is not separate from your mental health. It is one of the most honest reporters you have. Start paying attention to what it is telling you.
Gut Issues and Anxiety Running in Parallel?
I have specialized training in GI psychology and work virtually with adults across California and New York. If your stomach and your stress seem connected, they probably are. Visit drdgabay.com.
