Ear vagus nerve stimulation to improve motivation and insulin sensitivity

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

The study will enroll 60 adults with major depressive disorder and 60 matched control participants across a wide BMI and insulin-sensitivity range, including people with type 2 diabetes. Participants complete an intake with clinical interviews, fasting blood work, and a battery of reward and effort tasks, then wear a continuous glucose sensor and complete ecological momentary assessments for two weeks. Insulin sensitivity is measured with an oral glucose tolerance test while participants receive randomized acute transcutaneous auricular vagus nerve stimulation (tVNS) versus sham on separate days, and two randomized neuroimaging sessions use concurrent fMRI and electrogastrography to measure brain and stomach responses. The design is single-blind (participants), includes a minimum 2-day washout between stimulation conditions, and collects additional metabolic, questionnaire, and optional genetic biobank data to characterize participants.

Why it matters

Who can join: the full rules

Inclusion criteria:

* Participants with depression (DSM-5 diagnosis) or participants without depression (no DSM-5 diagnosis, lifetime)
* BMI between 18.5 and 40 kg/m²
* Age between 18 and 60 years
* Legally valid informed consent

Exclusion criteria:

The following diagnoses in medical history:

* Brain injury
* Schizophrenia
* Bipolar disorder
* Severe substance use disorder
* Coronary heart disease
* Stroke
* Epilepsy
* Chronic inflammatory diseases (e.g., rheumatoid arthritis, Crohn's disease, etc.)
* Type I diabetes

The following diagnoses within 12 months prior to the experiment:

* Obsessive-compulsive disorder
* Somatic symptom disorder
* Eating disorder

The following diagnoses in medical history for control participants:

* Depression
* Anxiety disorders (except specific phobias)

Generally:

* Contraindications for MRI (e.g., metal implants, claustrophobia) or taVNS (e.g., piercings, sore or diseased skin on the outer right ear)
* Pregnant and breastfeeding women will not be included
* Unclear capacity to consent
* Stomach surgeries affecting body weight (e.g., bypass surgeries)

Where it's running

• Section of Medical Psychology, Department of Psychiatry & Psychotherapy, Faculty of Medicine, University of Bonn
  Bonn, Germany Recruiting

Study contacts

• Principal investigator: Nils B Kroemer, Prof. Dr. — Section of Medical Psychology, Department of Psychiatry & Psychotherapy, Faculty of Medicine, University of Bonn, 53127 Bonn, Germany
• Study coordinator: Nils B Kroemer, Prof. Dr.
• Email: nkroemer@uni-bonn.de
• Phone: +49 228 287 11151

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.