Clinical and Neurobehavioral Changes With Weight Loss Drug Discontinuation and Reinitiation

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.