Participant Inclusion Criteria--
Functional Dyspepsia Group:
- Males and females; ages 18-65 years
- Rome V functional dyspepsia post-prandial distress syndrome subtype
- Negative upper endoscopy or upper GI series to rule out structural/organic cause for FD
- greater than or equal to 5.5 gut interoceptive awareness score (by VSI awareness subscale)
- Fluent in English
- Willing and able to provide informed consent
- Stable dose for 30 days prior to Visit 1 if on a neuropsychiatric medication (e.g., TCA, SNRI, SSRI mirtazapine, atypical antipsychotic, gabapentin, buspirone, pregabalin)
- No current plans to initiate a new or change dosing on a neuropsychiatric medication within the study period
Anorexia Nervosa Group:
- Males and females; ages 18-65 years
- DSM-5 anorexia restricting-type by the Eating Disorder Module in the Diagnostic Interview for Mood, Anxiety, and OCD and related Neuropsychiatric Disorders (DIAMOND)
- greater than or equal to 5.5 gut interoceptive awareness score (by VSI awareness subscale)
- Fluent in English
- Willing and able to provide informed consent
- Stable dose for 30 days prior to Visit 1 if on an SSRI
- No current plans to initiate a new neuromodulator
- No current plans to initiate a new SSRI or change dosing on an SSRI
Healthy Controls:
- Males and females; ages 18-65 years
- BMI greater than or equal to 18.5 kg/m2
- Fluent in English
- Willing and able to provide informed consent
Participant Exclusion Criteria--
Functional Dyspepsia Group:
- Presence of other conditions that could explain the patient's symptoms by medical chart:
- Pyloric or intestinal obstruction (by EGD, UGI, or Abdominal CT)
- Active H.pylori (by CLO test or stool antigen test)
- Active inflammatory bowel disease
- Eosinophilic gastroenteritis or eosinophilic esophagitis
- Acute renal failure
- Chronic renal failure (serum creatinine >3 mg/dL) and/or on hemodialysis or peritoneal dialysis
- Acute liver failure
- Any acute gastrointestinal process
- Any plausible structural or metabolic causes
- Heartburn as predominant symptom
- History of peptic ulcer
- Symptom resolution with antisecretory therapy (PPI use for other reasons that did not resolve FD symptoms will be allowed)
- Endorses any contraindications to MRI
- Body weight of 450 lbs or greater or BMI of 50 kg/m2 or greater (limit of MRI table)
- Allergy to pineapple (used in the test meal during MRI)
- History of GI tract surgery or any serious medical condition (e.g., cancer)
- Pregnancy/breastfeeding within the last 8 weeks
- Uncontrolled diabetes (indicated by HbA1c greater than or equal to 7%) by chart
- Narcotic analgesics greater than three days per week
- Cannabinoid use greater than three days per week
- Intellectual disability by history
- Illiteracy
- History of weight/shape-based eating disorder including anorexia nervosa by DIAMOND
- Current binge eating by DIAMOND
- Current self-induced vomiting by DIAMOND
- Current laxative or diuretic misuse by DIAMOND
- Current substance/alcohol use disorder within past year by DIAMOND
- Current/history of psychosis by DIAMOND
- Current mania by DIAMOND
- Active suicidal ideation by modified DIAMOND abbreviated suicide module; passive suicidal ideation is allowed
- Inability or unwillingness to consume food by mouth
- Inability to provide informed consent
Anorexia Nervosa Group:
- Diagnosis of chronic gastrointestinal disorder
- Rome V functional dyspepsia
- Endorses any contraindications to MRI
- Body weight of 450 lbs or greater or BMI of 50 kg/m2 or greater (limit of MRI table)
- Allergy to pineapple (used in the test meal during MRI)
- History of GI tract surgery or any serious medical condition (e.g., cancer)
- Pregnancy/breastfeeding within the last 8 weeks
- Uncontrolled diabetes (indicated by HbA1c greater than or equal to 7%) by chart
- Narcotic analgesics greater than three days per week
- Cannabinoid use greater than three days per week
- Intellectual disability by history
- Illiteracy
- Current binge eating by DIAMOND
- Current self-induced vomiting by DIAMOND
- Current laxative or diuretic misuse by DIAMOND
- Current substance/alcohol use disorder within past year by DIAMOND
- Current/history of psychosis by DIAMOND
- Current mania by DIAMOND
- Active suicidal ideation by DIAMOND abbreviated suicide module; passive suicidal ideation is allowed
- Inability or unwillingness to consume food by mouth
- Inability to provide informed consent
- Current use of neuropsychiatric medication other than an SSRI (e.g., TCA, SNRI, mirtazapine, atypical antipsychotic, gabapentin, buspirone, pregabalin)
Healthy Controls:
- Diagnosis of chronic gastrointestinal or pain disorder
- Rome V functional dyspepsia
- greater than or equal to 5.5 gut interoceptive awareness score (by VSI awareness subscale)
- Current use of a medication known to influence gastric sensorimotor functions (including neuromodulators and SSRIs)
- Active psychiatric disorder including a feeding/eating disorder by DIAMOND
- Endorses any contraindications to MRI
- Body weight of 450 lbs or greater or BMI of 50 kg/m2 or greater (limit of MRI table)
- Allergy to pineapple (used in the test meal during MRI)
- History of GI tract surgery or any serious medical condition (e.g., cancer)
- Pregnancy/breastfeeding within the last 8 weeks
- Uncontrolled diabetes (indicated by HbA1c greater than or equal to 7%) by chart
- Narcotic analgesics greater than three days per week
- Cannabinoid use greater than three days per week
- Intellectual disability by history
- Illiteracy
- Current binge eating by DIAMOND
- Current self-induced vomiting by DIAMOND
- Current laxative or diuretic misuse by DIAMOND
- Current substance/alcohol use disorder within past year by DIAMOND
- Current/history of psychosis by DIAMOND
- Current mania by DIAMOND
- Active suicidal ideation by DIAMOND modified suicide module; passive suicidal ideation is allowed
- Inability or unwillingness to consume food by mouth
- Inability to provide informed consent