Functional dyspepsia, GERD, and gastroparesis overlap heavily, so a normal endoscopy rarely localizes the cause.
PPI non-response usually signals a gut-brain disorder, not inadequate acid suppression.
Low-dose tricyclics and gut-directed hypnotherapy target the visceral hypersensitivity that acid suppression misses.
Treating the shared gut-brain axis can outperform managing upper and lower GI symptoms separately.
When the workup is clean but symptoms persist
Many persistent upper GI disorders – including functional dyspepsia, reflux hypersensitivity, and functional heartburn – are disorders of gut-brain interaction rather than acid or motility problems, which is why they persist despite a normal workup and PPI therapy.¹ Managing them effectively means targeting the gut-brain axis directly, with gut-brain neuromodulators or gut-directed hypnotherapy, rather than escalating acid suppression.
Few presentations test clinical judgment like persistent upper GI symptoms. The workup is often clean, the trial of acid suppression only partly helps, and the patient returns no better than before. The instinct is to escalate the dose or repeat the scope. But a large share of these patients are not under-treated for an organic disease. They are being treated for the wrong mechanism.
Functional dyspepsia vs GERD vs gastroparesis: why they overlap
Functional dyspepsia, GERD, and gastroparesis overlap because they produce the same symptoms – heartburn, epigastric pain, early satiety, nausea, and bloating – from different underlying mechanisms, so presentation alone rarely separates them.¹ Add the esophageal hypersensitivity disorders and the phenotypes blur further, sharing those symptoms in almost every combination.
The Rome IV framework made this explicit for the functional disorders, splitting functional dyspepsia into postprandial distress syndrome and epigastric pain syndrome, and separating true GERD from functional heartburn and reflux hypersensitivity – conditions that look identical at the bedside but respond very differently to acid suppression.¹ The practical consequence is that a normal endoscopy and a partial PPI response do not localize the problem. They often point away from acid altogether.
Gastroparesis blurs the picture further. Delayed emptying and functional dyspepsia overlap substantially in symptoms and even in physiology, and the ACG now cautions that emptying studies correlate poorly with symptom severity.² A patient's dominant complaint is a more reliable guide to management than a single motility number.
Clinical reference: differentiating upper GI conditions
Condition
What testing shows
PPI response
GERD (erosive or NERD)
Abnormal acid exposure; positive symptom association
Responds
Reflux hypersensitivity
Normal acid exposure; positive symptom association
Partial or poor
Functional heartburn
Normal acid exposure; no symptom association
Poor
Functional dyspepsia
Gastric-origin symptoms; not defined by acid testing
Poor to partial
Gastroparesis
Delayed gastric emptying, weakly linked to symptoms
Poor
Why PPIs stop working: the gut-brain signal
PPI non-response usually signals a disorder of gut-brain interaction, not inadequate acid suppression,¹ and it is one of the most useful – and most commonly misread – findings in upper GI practice. When symptoms persist despite adequate acid suppression, three gut-brain mechanisms are typically amplifying signals that would otherwise stay below awareness³:
Visceral hypersensitivity – a lowered threshold at which normal luminal and mechanical stimuli are perceived as painful.
Impaired gastric accommodation – the fundus fails to relax normally after a meal, driving early satiety and postprandial distress.
Symptom hypervigilance – heightened central attention to gut sensation that sustains and amplifies the symptom.
This is why prokinetics and escalating acid suppression so often disappoint in functional dyspepsia and reflux hypersensitivity.³ They target secretion and motility while the driver sits in sensory processing and central modulation. Recognizing that shift – from an end-organ model to a gut-brain one – is what separates a productive next step from another unrewarding trial.
Neuromodulators and brain-gut therapy for functional dyspepsia
Once the focus shifts from the acid to the gut-brain axis, two approaches do the real work – and they work best together. The first is brain-gut behavioral therapy, including gut-directed hypnotherapy, now recognized by the Rome Foundation and major gastroenterology bodies as first-line care for disorders of gut-brain interaction, functional dyspepsia included.⁷
On the medication side, low-dose tricyclics can help when acid suppression hasn't; the British Society of Gastroenterology supports them, started low (amitriptyline 10 mg) and built up slowly, while SSRIs and SNRIs don't carry the same evidence.³
And when it's post-meal fullness that dominates, buspirone – which relaxes the upper stomach – eased early satiation, fullness, and bloating in a placebo-controlled trial.⁶ One thing matters as much as the choice itself: how you introduce it. Taking a moment to explain the gut-brain rationale to a patient isn't a preamble to treatment – it's part of what makes it work.
Of these, gut-directed hypnotherapy has the longest track record. It sits comfortably alongside medication and dietary changes – sometimes from the start, sometimes once those haven't fully settled things – because it works on a different part of the problem.
In one randomized trial, patients were still doing better a full year on – at 56 weeks – with hypnotherapy outperforming both standard medical care and supportive therapy.⁴ That makes sense once you think about what's really driving the symptoms: hypnotherapy settles the oversensitive gut-brain signaling that acid- and diet-focused care alone doesn't reach.
Clinical reference: finding the right fit for functional dyspepsia
From brain-gut therapy to targeted medications – what each option offers, who it fits, and the evidence behind it.
Option
Best for
Evidence in FD
Gut-directed hypnotherapy
First-line; any FD type
Guideline-recognized first-line for DGBIs; lasting benefit to 56 weeks4,7
Effective when acid suppression hasn't worked; start low, titrate slowly3
Buspirone (10 mg before meals)
Postprandial distress syndrome
Improved satiation, fullness, and bloating in an RCT6
SSRIs / SNRIs
Not indicated
Not supported for functional dyspepsia3
How each option works
Gut-directed hypnotherapy – a brain-gut behavioral therapy
Amitriptyline – a low-dose tricyclic (TCA) neuromodulator
Buspirone – a fundus-relaxing 5-HT1A agonist
SSRIs / SNRIs – central neuromodulators, with no evidence in functional dyspepsia
Managing overlapping IBS and upper GI symptoms
Overlapping IBS and upper GI symptoms are best managed by treating the shared gut-brain axis rather than each region in isolation, because the two commonly coexist and respond to the same brain-gut approach.⁵
Most patients don't arrive with a single, tidy diagnosis: the IBS patient with early satiety and reflux, or the functional dyspepsia patient with a lower-GI component, is the rule rather than the exception, and this is where a gut-brain approach earns its place.
Emerging real-world data are beginning to quantify this. A recent analysis of 628 users of the Nerva gut-directed hypnotherapy program found that people with IBS and concurrent upper GI symptoms achieved a greater reduction in IBS symptom severity than those without upper GI involvement – the first published signal that a structured brain-gut program may benefit the whole-gut phenotype rather than the lower GI tract alone.⁵
It is early evidence from a conference abstract, not a controlled trial, and dedicated work on esophageal gut-brain disorders is currently underway rather than reported. But it reinforces a principle experienced clinicians already sense: when symptoms span the gut, treating the shared axis often beats treating each segment in turn.
For the patient in front of you who has cycled through acid suppression without relief, the most useful question may not be which drug next. It is whether the mechanism has been correctly identified at all.
Frequently asked questions
How do you distinguish functional heartburn from reflux hypersensitivity and true GERD?
The distinction rests on pH-impedance monitoring with symptom-association analysis, not symptoms alone, since all three present with indistinguishable heartburn. True GERD shows pathological acid exposure, reflux hypersensitivity shows normal exposure but a positive symptom association, and functional heartburn shows neither.¹
When should a neuromodulator be considered in functional dyspepsia?
A gut-brain neuromodulator is a reasonable second-line step once acid suppression and, where relevant, prokinetics have failed to control symptoms. Low-dose tricyclics have the strongest evidence in functional dyspepsia, whereas SSRIs and SNRIs do not, and slow titration with a clear rationale improves tolerability.³
Does delayed gastric emptying confirm gastroparesis rather than functional dyspepsia?
Emptying studies correlate poorly with symptom severity and overlap substantially with functional dyspepsia, so a delayed result does not by itself explain a patient's symptoms.² Management is often better guided by the dominant symptom pattern than by the emptying number alone.
What is the evidence for gut-directed hypnotherapy in upper GI disorders?
Randomized evidence dates back to a 2002 trial showing gut-directed hypnotherapy produced durable functional dyspepsia improvement out to 56 weeks and reduced medication use.⁴ Evidence in upper GI disease remains earlier-stage than in IBS, with recent real-world data suggesting benefit in patients whose IBS coexists with upper GI symptoms.⁵
Patient resources to share
Patients often leave with more questions than answers. These explainers help fill that gap in plain language – download the PDF or share the links below.
Patient resources
Reflux, indigestion, & regurgitation
Making sense of your symptoms: simple to understand, helping you feel understood.
What is GERD? Gastroesophageal reflux disease explained
What separates GERD from everyday heartburn – and how to keep reflux in check.
Camilleri M, Kuo B, Nguyen L, et al. ACG clinical guideline: gastroparesis. Am J Gastroenterol. 2022;117(8):1197-1220.
Black CJ, Paine PA, Agrawal A, et al. British Society of Gastroenterology guidelines on the management of functional dyspepsia. Gut. 2022;71(9):1697-1723.
Calvert EL, Houghton LA, Cooper P, Morris J, Whorwell PJ. Long-term improvement in functional dyspepsia using hypnotherapy. Gastroenterology. 2002;123(6):1778-1785.
Noorani S, Brand D, Naoumidis C, Hall C, Smith MS, Jodorkovsky D, Luo Y. Brain-gut behavioral therapy program for IBS benefits patients with concurrent upper GI symptoms [abstract Mo1780]. Gastroenterology. 2026. doi:10.1016/S0016-5085(26)04658-5.
Tack J, Janssen P, Masaoka T, Farré R, Van Oudenhove L. Efficacy of buspirone, a fundus-relaxing drug, in patients with functional dyspepsia. Clin Gastroenterol Hepatol. 2012;10(11):1239-1245.
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