Inclusion Criteria:

• Adults over the age of 18.

• Fulfilled Rome V diagnostic criteria for functional dyspepsia postprandial distress syndrome subtype, with or without epigastric pain syndrome.

• A total score of at least 3 on the Gastroparesis Cardinal Symptom Index (GCSI) indicating symptom severity to be moderate or higher.

• Normal gastric emptying as confirmed by standard gastric emptying testing (if such a testing was clinically done).

• Upper endoscopy negative to rule out structural or organic etiologies for GI symptoms (within last 1 year).

• Fluent in English language.

• Able to provide informed consent and comply with study procedures

Exclusion Criteria:

• Evidence of organic gastrointestinal disease or surgical history that could explain participant symptoms (e.g., peptic ulcer disease, celiac disease, inflammatory bowel disease, eosinophilic gastritis or eosinophilic esophagitis, malignancy).

• Current or recent (within the past 12 months) eating disorder such as anorexia nervosa or bulimia nervosa. Historical eating disorder diagnosis may also be exclusionary if residual disordered eating patterns, fear of weight gain, or food-related body image concerns are judged by the investigator to potentially confound symptom interpretation or participation.

• Underweight BMI (<17 kg/m²) or evidence of clinically significant unintentional weight loss (>25% body weight in 6 months). 

• Current use of enteral or parenteral nutrition for >50% of caloric needs and/or participant unwillingness to reduce use of enteral or parenteral nutrition at the time of study enrollment.

• History of developmental or intellectual disability, current cognitive impairment that would preclude participation, or other neurological illness impairing cognitive functioning. 

• Active suicidal ideation, suicide attempt within the past 12 months, severe psychiatric illness, severe depressive symptomatology, acute distress, or other symptomatology that, in the investigator’s judgment, would necessitate a different level of psychiatric care and/or prevent full engagement in psychological intervention sessions or adherence to study procedures.

• Medical disability or any unstable systemic illness (e.g., decompensated hepatic, cardiac, renal, or neurological disease) that could interfere with participation, comprehension, or safety in psychological intervention sessions.

• Current daily cannabis use (inhaled, edible, or medical). Other substance use or misuse of prescription medications may also be exclusionary if substance use patterns are judged by the investigator to potentially confound symptom interpretation or participation.

• Current pregnancy or lactation.

• Inability or unwillingness of individual or legal guardian/representative to give informed consent.

• Non-fluent in English, or any condition that would limit compliance or follow-up

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 04/01/2026. Questions regarding updates should be directed to the study team contact.