Clinical and Neurobehavioral Changes With Weight Loss Drug Discontinuation and Reinitiation

Clinical and Neurobehavioral Changes With GLP-1 (Glucagon-like Peptide-1) Discontinuation

The goal of this clinical study with research procedures is to learn how stopping and restarting tirzepatide (a medication that helps regulate blood sugar and appetite) affects brain activity, behavior, and health in adults ages 18-70 who are currently taking tirzepatide. Specifically, the study aims to examine how a short pause in tirzepatide affects hunger, mood, sleep, and daily functioning; how stopping and restarting tirzepatide alters brain chemistry and brain responses to food-related images; and how these changes relate to health measures such as quality of life and emotional well-being. There is no comparison group; instead, researchers will assess changes within each participant across three time points: while taking tirzepatide, after stopping it for 3-4 weeks, and after restarting it for 6-8 weeks. Participants will attend three in-person visits lasting approximately 3-4 hours each, during which they will complete interviews, questionnaires, and cognitive tasks; provide a urine sample (pregnancy screening for females); undergo a brain scan using magnetic resonance imaging (MRI) and MR spectroscopy (MRS); and receive a kit to provide a small stool sample. Participants will also complete two brief check-in phone calls between visits and the online BrainHealth Index between sessions, which includes surveys and cognitive tasks. All changes to tirzepatide use will occur under the supervision of a study physician to support participant safety and comfort, and the total study duration is approximately 13 weeks.

This study specifically recruits individuals currently being prescribed for tirzepatide. The experimental design will consist of a brief discontinuation of the drug for roughly 3-4 weeks followed by a reinitiation of the medication. Prescription and administration of tirzepatide is done as part of normal patient care and is not a component of the study.

Inclusion Criteria:

• Aged 18-70 years.
• Currently on tirzepatide.
• Currently receiving care from University of Texas- Southwestern (UTSW) Weight Wellness Clinic.
• Cognitively capable of understanding and signing informed consent.
• Be proficient in English.

Exclusion Criteria:

• History of major neurological or psychiatric disorders, including substance use disorders that might confound brain imaging results (e.g., stroke, epilepsy, multiple sclerosis, schizophrenia, major depression requiring hospitalization).
• Diagnosis of Type 2 Diabetes.
• Current diagnosis of an eating disorder.
• Use of medications affecting weight other than tirzepatide.
• Pregnancy or breastfeeding.
• MR contraindications:
• Heart pacemaker, heart valve replacement, or aortic clips
• Metal fragments in the eyes, skin, or elsewhere in the body
• Brain clips or pieces of metal used in aneurysm surgery or intercranial bypass
• Venous umbrella
• Pieces of metal in the body resulting from work as a sheet-metal worker or welder
• Clips placed in an internal organ
• Prosthetic devices, such as middle ear, eye, joint, or penile implants
• Joint replacement
• Hearing aid that cannot be removed
• Neurostimulator
• Insulin pump
• Shunts or stents
• Metal mesh or coil implants
• Metal plate, pin, screws, or wires, or any other metal implants