Compulsive Eating and Brain's Reward System in Different Pathologies (BI-POTATOS)

Bipolar Disorders, Parkinson's Disease, ObesiTy and Compulsive eAting: TransnosOlogical Assessement of the Brain's Reward System

Compulsive eating behaviors represent a significant issue across various disorders such as Parkinson's disease, bipolar disorders, and obesity.

Despite their apparent differences, these conditions share common underlying disturbances involving the brain's reward system, particularly within dopaminergic networks.6,7 Previous neuroimaging studies have consistently reported reward system connectivity impairment associated with compulsive eating, in each of these disorders. However, few studies have simultaneously explored the neurobiological similarities and specificities of this common symptom, eating behavior, when occurring in different populations and disorders.

The Bi-POTATOS project proposes an original and innovative approach by adopting a transdiagnostic perspective, employing brain imaging and comprehensive psycho-behavioral assessments to investigate common behavioral characteristics and neural circuit alterations associated with compulsive eating across these three conditions. For the first time, this study will allow a direct comparison of the cerebral signatures linked to compulsive eating behavior, clearly distinguishing between transdiagnostic vulnerabilities and features unique to each clinical condition.

The central hypothesis is that similar dysfunctions in brain regions involved in motivation and impulsive decision-making underpin compulsive eating behaviors, irrespective of the initial diagnosis. However, the underlying pathology may modulate these mechanisms, introducing certain specificities.

By clarifying these common mechanisms, the Bi-POTATOS project will not only enhance our understanding of the neurobiological etiology of these disorders but also pave the way for innovative, targeted therapeutic interventions. This project will precisely identify whether specific neural alterations constitute a universally relevant therapeutic target, or conversely, determine which alterations necessitate tailored therapeutic strategies based on the underlying pathology.

Study Overview

• Status: Not yet recruiting
• Conditions: Bipolar 1 Disorder; PARKINSON DISEASE (Disorder); Obesity (BMI>30)
• Intervention / Treatment: Other: MRI/ MRS (Magnetic Resonance Imaging /Magnetic Resonance Spectroscopy)

• Study Type: Interventional
• Enrollment (Estimated): 150
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Lise Laclautre; Phone Number: +33473754963; Email: promo_interne_drci@chu-clermontferrand.fr

Study Locations

• France
  • Clermont-Ferrand, France, 63000
    • CHU de Clermont-Ferrand
    • Contact: Lise Laclautre; Email: promo_interne_drci@chu-clermontferrand.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• 1-Common Criteria (Parkinson disease, Obesity, Bipolar patients)

• Men or women, right-handed, 18 to 80 years old

• With or without compulsive eating according to the QEWP-R

• No changes to long-term treatments in the previous month

• Cooperation and understanding to strictly comply with the conditions set out in the protocol

• Acceptance of the protocol and signing of a written informed consent

• Affiliation to the social security system

  2-Specific criteria Parkinsonian patients (n=25 with CE, n=25 without CE)

• Diagnosis of Parkinson's disease according to the Movement Disorders Society criteria

• BMI<30

Obese patients (n=25 with CE, n=25 without CE)

• Obese patients according to HAS 2022 classification
• BMI≥30

Bipolar patients (n=25 with CE, n=25 without CE)

• Diagnosis of bipolar disorder according to DSM 5 criteria
• BMI<30

Exclusion Criteria:

• 1-Common Criteria

• Dementia (MoCA <22)

• Severe depression (Beck Depression Inventory>30)

• Contraindications to MRI (implanted stimulator, insulin pump, intraocular metallic foreign bodies or close to the nervous and vascular systems, claustrophobia, non-removable dental appliance, tattoo on the face or neck, …)

• Refusal to be informed in case of incidental finding on MRI

• History of stroke or brain trauma that may impact MRI findings

• Patients under guardianship, deprived of freedoms or protection of justice.

• Pregnant women, breastfeeding women

  2- Specific criteria

Parkinsonian patients:

• People suffering from neurological pathologies other than PD
• Patient suffering from psychiatric disorder
• Treated with deep brain stimulation
• Patients with severe tremor (> 3 for a tremor sub-item of the MDS-UPDRS III) or excessively severe dyskinesia contraindicating MRI

Obese patients:

• Suffering from progressive neurological pathology and psychiatric disorder
• Weight >220kg contraindicating MRI
• Body (Shoulder) diameter > 220 cm contraindicating MRI
• History of bariatric surgery
• GLP1 treatment

Bipolar patients:

• Suffering from neurological pathology and psychiatric disorder other than bipolar disorder
• Current acute depressive or hypomanic episode according to DSM 5
• Treated with deep brain stimulation or vagus nerve stimulation
• Electroconvulsivotherapy < 6 months

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Study Group; Visit 1 : selection visit; Inform consent and participation agreement; Assessment of the disease and eating behavior disorder severity, medication taken, as well as a standard medical examination (measurement of weight, height and blood pressure) Cognitive function, impulsive trait of personality, depression, anxiety, restless legs syndrome, REM sleep behavior disorder and pain will be assessed. Visit 2 : investigational visit; MRI scan; neuropsychological assessments

Other: MRI/ MRS (Magnetic Resonance Imaging /Magnetic Resonance Spectroscopy); Neuropsychological assessment : motor impulsivity, motor inhibition, cognitive impulsivity (Stroop); decision making in an ambiguous context (Iowa Gambling Task), time perception (delay discounting reward task) and risk taking (Balloon analog Risk task). MRI : The subjects will be scanned using a 3-Tesla MAGNETOM Vida scanner (Siemens, Erlangen, Germany) with a 64 channel head coil Dietician : 3 days food record; Other Names: Neuropsychological assessments; Dietitian

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of resting state seed-based functional connectivity from the limbic striatum (seed: ventral striatum) by MRI.	MRI is a 3-Tesla MAGNETOM Vida scanner (Siemens, Erlangen, Germany) with a 64 channel head coil. The subjects were asked to hold still, with their eyes open and not to think of anything particular. Foam padding was employed to reduce head movement and earplugs were used to reduce scanner noise. The high resolution anatomical images were obtained through a T1-weighted magnetization-prepared rapid gradient echo (MPRAGE) sequence with the following parameters: repetition time (TR): 2300 ms, echo time (TE): 3.08 ms, inversion time (IT): 900 ms, flip angle (FA): 9°, matrix: 288 x 288, 176 slices, slice thickness: 1mm. Resting-state functional MRI images were obtained using an EPI sequence with the following parameters: TR: 3000ms, TE: 30ms, FA: 81°, field of view (FOV): 192 mm, 55 slices, slice thickness: 3.3 mm, gap between slices: 3.3 mm, pixel bandwidth: 2441 Hz/Pixel, number of time points: 180, acquisition duration: 9 minutes).	At visit 2, between 1 and 12 weeks after patient enrollment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Demographical data	sex	at visit 1, selection visit - Day 0
Demographical data	Age (year)	at visit 1, selection visit - Day 0
Demographical data	weight (kg)	at visit 1, selection visit - Day 0
Demographical data	size (m)	at visit 1, selection visit - Day 0
Parkinson Disease severity	Assessment of parkinson desease with the MDS-UPDRS (Movement Disorders Society - Unified Parkinson's Disease Rating Scale ) scale, completed by the investigator.	at visit 1, selection visit - Day 0
Bipolar Disease severity	Assessment of bipolar desease with MADRS (Montgomery-Asberg Depression Rating Scale) and YMRS (Young Mania Rating Scale) scale, completed by the investigator.	at visit 1, selection visit - Day 0
Obesity disease severity	Obesity classification according to Health French Agency (Haute Autorité de Santé) 2022, completed by the investigator.	at visit 1, selection visit - Day 0
Impulsive trait of Personality according the Barratt impulsiveness scale (BIS-11)	This self questionnaire is completed by the patient during the selection visit	at visit 1, selection visit - Day 0
Eating behavior disorder severity	Self reported eating behavior disorder using 3 questionnaires (QEWP5 (Questionnaire on Eating and Weight Patterns5), DEBQ (Dutch Eating Behaviour Questionnaire) and food craving questionnaire))	at visit 1, selection visit - Day 0
Presence of Anxiety and/or depression according the Beck depression and anxiety scale	These self questionnaires is completed by the patient during the selection visit	at visit 1, selection visit - Day 0
Presence of restless legs syndrome according the International Restless Legs Syndrome (Rating Scale)	This questionnaire is completed by the investigator during the selection visit	at visit 1, selection visit - Day 0
Intensity and Pain caracteristics	Patients will evaluate their pain using 2 self questionnaires (3-PDQ, BPI (Brief Pain Inventory))	at visit 1, selection visit - Day 0
Impulsive compulsive behaviors rating scale for PD (QUIP-RS)	The QUIP-RS is a brief 28-item patient-reported or clinician-rated scale developped for measure of severity of ICDs. Each item is rated on a 5-point Likert scale assessing frequency of symptoms with a range of scores from 0 (never) to 4 (very often).	at visit 2, between 1 and 12 weeks after selection visit
Spontaneous food intake	Patients will report thier spontaneous food intake for 3 days using a dietary data collected. Patient nutritional intakes will be analysed using Nutrilog software	at visit 2, between 1 and 12 weeks after selection visit
Motor impulsivity (Go/No Go task)	Motor impulsivity will be assessed with the Go/No-go task. It is a simple experimental paradigm that requires participants to respond as quickly as possible (Go) to a particular class of stimuli, for example by pressing a key on a keyboard, and not to respond to other classes of stimuli (No Go). The key behaviour measured with this experiment is the participants' ability to withhold a response on No-go trials.	at visit 2, between 1 and 12 weeks after selection visit
Motor inhibition (Stop Signal Task (SST))	The Stop Signal Task (SST) is a test that measures motor inhibition. The participant must respond quickly to Go stimuli but interrupt their response when a stop signal appears. The key index, the Stop Signal Reaction Time (SSRT), reflects the time required to stop an ongoing action. This test will be performed by neuropsychologist.	at visit 2, between 1 and 12 weeks after selection visit
Iowa Gambling Task (IGT)	IGT assesses risk-based learning by relying on a system of rewards and punishments within a simulated context of uncertainty, representing a real-life decision-making situation. Participants choose cards from four decks, each associated with varying amounts of monetary gains and losses. Over time, advantageous decks yield higher net rewards, while disadvantageous decks lead to net losses. Performance on the task reflects an individual's capacity to balance immediate rewards against long-term outcomes, thereby providing insight into adaptive decision-making and risk evaluation processes. This test will be performed by neuropsychologist.	at visit 2, between 1 and 12 weeks after selection visit.
Cognitive impulsivity (Stroop)	The Stroop Test is a cognitive task designed to evaluate attentional control and the ability to inhibit automatic responses when faced with conflicting information. Participants are asked to name the color of the ink in which words are printed, even when the word itself refers to a different color (e.g., GREEN printed in red ink). This requires suppressing the automatic tendency to read the word and instead focusing on the ink color. The difference in performance between congruent and incongruent conditions, known as the Stroop interference effect, is a key indicator of cognitive inhibition and executive control. This test will be performed by neuropsychologist.	at visit 2, between 1 and 12 weeks after selection visit
Time perception (delay discounting reward task)	Participants make choices between two alternatives: a larger reward available after a delay (across seven delay intervals) and a smaller reward available immediately. The value of the immediate reward is systematically adjusted, either increasing or decreasing, in separate blocks. The task assesses preferences for immediate versus delayed gratification using two reward types: money and food. This test will be performed by neuropsychologist.	at visit 2, between 1 and 12 weeks after selection visit
Balloon analog Risk task	Participants are given 30 balloons (by default). For each balloon, they can choose either to inflate it further or to collect their earnings. With each successful inflation, they can earn money. However, if a balloon bursts before the participant collects the potential earnings, they lose all potential gains associated with that balloon. The average number of pumps on balloons that do not burst is the primary dependent variable in this paradigm. A higher number of pumps reflects increased risk-taking behavior. This test will be performed by neuropsychologist.	at visit 2, between 1 and 12 weeks after selection visit
Surface based (Freesurfer) and Voxel based (SPM) morphometry performed by MRI	MRI is a 3-Tesla MAGNETOM Vida scanner (Siemens, Erlangen, Germany) with a 64 channel head coil. The subjects were asked to hold still, with their eyes open and not to think of anything particular. Foam padding was employed to reduce head movement and earplugs were used to reduce scanner noise. The high resolution anatomical images were obtained through a T1-weighted magnetization-prepared rapid gradient echo (MPRAGE) sequence with the following parameters: repetition time (TR): 2300 ms, echo time (TE): 3.08 ms, inversion time (IT): 900 ms, flip angle (FA): 9°, matrix: 288 x 288, 176 slices, slice thickness: 1mm. Resting-state functional MRI images were obtained using an EPI sequence with the following parameters: TR: 3000ms, TE: 30ms, FA: 81°, field of view (FOV): 192 mm, 55 slices, slice thickness: 3.3 mm, gap between slices: 3.3 mm, pixel bandwidth: 2441 Hz/Pixel, number of time points: 180, acquisition duration: 9 minutes).	at visit 2, between 1 and 12 weeks after selection visit
Structural connectivity (MRtrix and TRACTseg) performed by MRI	MRI is a 3-Tesla MAGNETOM Vida scanner (Siemens, Erlangen, Germany) with a 64 channel head coil. The subjects were asked to hold still, with their eyes open and not to think of anything particular. Foam padding was employed to reduce head movement and earplugs were used to reduce scanner noise. The high resolution anatomical images were obtained through a T1-weighted magnetization-prepared rapid gradient echo (MPRAGE) sequence with the following parameters: repetition time (TR): 2300 ms, echo time (TE): 3.08 ms, inversion time (IT): 900 ms, flip angle (FA): 9°, matrix: 288 x 288, 176 slices, slice thickness: 1mm. Resting-state functional MRI images were obtained using an EPI sequence with the following parameters: TR: 3000ms, TE: 30ms, FA: 81°, field of view (FOV): 192 mm, 55 slices, slice thickness: 3.3 mm, gap between slices: 3.3 mm, pixel bandwidth: 2441 Hz/Pixel, number of time points: 180, acquisition duration: 9 minutes).	at visit 2, between 1 and 12 weeks after selection visit
Resting state seed-based functional connectivity from the limbic striatum performed by MRI	MRI is a 3-Tesla MAGNETOM Vida scanner (Siemens, Erlangen, Germany) with a 64 channel head coil. The subjects were asked to hold still, with their eyes open and not to think of anything particular. Foam padding was employed to reduce head movement and earplugs were used to reduce scanner noise. The high resolution anatomical images were obtained through a T1-weighted magnetization-prepared rapid gradient echo (MPRAGE) sequence with the following parameters: repetition time (TR): 2300 ms, echo time (TE): 3.08 ms, inversion time (IT): 900 ms, flip angle (FA): 9°, matrix: 288 x 288, 176 slices, slice thickness: 1mm. Resting-state functional MRI images were obtained using an EPI sequence with the following parameters: TR: 3000ms, TE: 30ms, FA: 81°, field of view (FOV): 192 mm, 55 slices, slice thickness: 3.3 mm, gap between slices: 3.3 mm, pixel bandwidth: 2441 Hz/Pixel, number of time points: 180, acquisition duration: 9 minutes).	at visit 2, between 1 and 12 weeks after selection visit

Collaborators and Investigators

• Sponsor: University Hospital, Clermont-Ferrand

Study record dates

Study Major Dates

• Study Start (Estimated): December 1, 2026
• Primary Completion (Estimated): July 1, 2029
• Study Completion (Estimated): October 1, 2029

Study Registration Dates

• First Submitted: July 27, 2026
• First Submitted That Met QC Criteria: November 2, 2026
• First Posted (Actual): November 6, 2026

Study Record Updates

• Last Update Posted (Actual): November 6, 2026
• Last Update Submitted That Met QC Criteria: November 2, 2026
• Last Verified: November 1, 2026

More Information

Terms related to this study

• Keywords: reward system; compulsive eating; brain functional signatures
• Additional Relevant MeSH Terms: Synucleinopathies; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Mental Disorders; Nutrition Disorders; Overnutrition; Body Weight; Neurodegenerative Diseases; Movement Disorders; Overweight; Parkinsonian Disorders; Basal Ganglia Diseases; Behavior, Addictive; Compulsive Behavior; Impulsive Behavior; Feeding and Eating Disorders; Pathological Conditions, Signs and Symptoms; Behavior; Nutritional and Metabolic Diseases; Signs and Symptoms; Food Addiction; Obesity; Parkinson Disease; Investigative Techniques; Health Care Facilities Workforce and Services; Health Personnel; Chemistry Techniques, Analytical; Spectrum Analysis; Magnetic Resonance Spectroscopy; Nutritionists
• Other Study ID Numbers: AOI 2025 MARQUES; 2026-A00850-51 (Other Identifier: ANSM)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No