“Ozempic’s Next Act: People Taking the Drug for Weight Loss Say They Have Also Stopped Drinking, Smoking, Shopping, and Even Nail-Biting”, 2023-05-19 ():
All her life, Victoria Rutledge thought of herself as someone with an addictive personality. Her first addiction was alcohol. After she got sober in her early 30s, she replaced drinking with food and shopping, which she thought about constantly. She would spend $500 on organic groceries, only to have them go bad in her fridge. “I couldn’t stop from going to that extreme”, she told me. When she ran errands at Target, she would impulsively throw extra things—candles, makeup, skin-care products—into her cart…They have reported losing interest in a whole range of addictive and compulsive behaviors: drinking, smoking, shopping, biting nails, picking at skin.
…GLP-1 analogs appear to actually bind to receptors on neurons in several parts of the brain, says Scott Kanoski, a neurobiologist at the University of Southern California. When Kanoski and his colleagues blocked these receptors in rodents, the first-generation drugs exenatide and liraglutide became less effective at reducing food intake—as if this had eliminated a key mode of action. The impulse to eat is just one kind of impulse though. That these drugs work on the level of the brain—as well as the gut—suggests that they can suppress the urge for other things too.
In particular, GLP-1 analogs affect dopamine pathways in the brain, a.k.a the reward circuitry. This pathway evolved to help us survive; simplistically, food and sex trigger a dopamine hit in the brain. We feel good, and we do it again. In people with addiction, this process in the brain shifts as a consequence or cause of their addiction, or perhaps even both. They have, for example, fewer dopamine receptors in part of the brain’s reward pathway, so the same reward may bring less pleasure.
In lab animals, addiction researchers have amassed a body of evidence that GLP-1 analogs alter the reward pathway: mice on a version of exenatide get less of a dopamine hit from alcohol; rats on the same GLP-1 drug sought out less cocaine; same for rats and oxycodone. African vervet monkeys predisposed to drinking alcohol drank less on liraglutide and exenatide. Most of the published research has been conducted with these two first-generation GLP-1 drugs, but researchers told me to expect many studies with semaglutide, with positive results, to be published soon.
In humans, the science is much more scant. A couple of studies of exenatide in people with cocaine-use disorder were too short or small to be conclusive. Another study of the same drug in people with alcohol-use disorder found that their brain’s reward centers no longer lit up as much when shown pictures of alcohol while they were in an fMRI machine. The patients in the study as a whole, however, did not drink less on the drug, though the subset who also had obesity did. Experts say that semaglutide, if it works at all for addiction, might end up more effective in some people than others. “I don’t expect this to work for everybody”, says Anders Fink-Jensen, a psychiatrist at the University of Copenhagen who conducted the alcohol study. (Fink-Jensen has received funding from Novo Nordisk, the maker of Ozempic and Wegovy, for separate research into using GLP-1 analogs to treat weight gain from schizophrenia medication.) Bigger and longer trials with semaglutide could prove or disprove the drug’s effectiveness in addiction—and identify whom it is best for.
Semaglutide does not dull all pleasure, people taking the drug for weight loss told me. They could still enjoy a few bites of food or revel in finding the perfect dress; they just no longer went overboard. Anhedonia, or a general diminished ability to experience pleasure, also hasn’t shown up in cohorts of people who take the drug for diabetes, says Elisabet Jerlhag Holm, an addiction researcher at the University of Gothenburg. Instead, those I talked with said their mind simply no longer raced in obsessive loops. “It was a huge relief”, says Kimberly Smith, who used to struggle to eat in moderation. For patients like her, the drug tamed behaviors that had reached a level of unhealthiness.
…Doctors have noted a curious link between addiction and another obesity treatment: Patients who undergo bariatric surgery sometimes experience “addiction transfer”, where their impulsive behaviors move from food to alcohol or drugs. Bariatric surgery works, in part, by increasing natural levels of GLP-1, but whether the same transfer can happen with GLP-1 drugs still needs to be studied in longer trials.