TMS Appears to Cut Cravings, Food Intake in Obese Patients

Marlene Busko

June 15, 2016

NEW ORLEANS — A 9-week study of 16 obese patients who received repetitive transcranial magnetic stimulation (TMS) or a sham treatment suggests that TMS may help obese patients reduce cravings and shed pounds — but these are very early days, and the findings needs to be replicated in much longer, larger studies to confirm safety and efficacy, researchers caution.

Livio Luzi, MD, professor of physiology at the University of Milan and San Raffaele Scientific Institute, in Milan, Italy, presented his findings during a session on weight-loss intervention methodology on June 12 at the American Diabetes Association (ADA) 2016 Scientific Sessions.

"The idea came to me when I heard a presentation in Europe where psychiatrists were using this technique for addiction disorders," he told Medscape Medical News. The procedure was approved about 7 years ago by the US Food and Drug Administration to treat major depression. Moreover, European regulators recently approved TMS for smoking cessation and a recent study (Biol Psychiatry. 2013;73: 714-720) showed benefit for this, he noted.

Repetitive TMS works by stimulating the reward centers of the brain, and since "obesity can be considered a food addiction and the reward pathway is the same" as in other addictions, Dr Luzi speculated that TMS could quell food cravings — which it did in this 9-week study. Now "I am waiting for the results at 6 months" from the ongoing study, he said.

"It's the most impressive thing I've seen at the whole meeting," session moderator Frederico GS Toledo, MD, associate professor of medicine at the University of Pittsburgh, Pennsylvania enthused to Dr Luzi.

To Medscape Medical News, he commented, "It is very promising preliminary data and has the potential to become a groundbreaking alternative, but it's very important that we do the 6-month or even longer efficacy studies and long-term safety studies" and also look at weight-loss maintenance, he added.

To date, there are a few options to treat obesity — lifestyle modification, drugs, devices such as gastric balloons, and bariatric surgery, he continued. "If this research evolves and shows efficacy and safety, [TMS] would be [another] option, and that's why I think it is so important and very promising preliminary data," Dr Toledo summarized.

Altering the Brain's Reward Pathway

When obese people are given pictures of their favorite foods, their "reward system" areas of the brain light up, but dopamine release is blunted compared with the response in normal-weight patients, so they tend to overeat, Dr Luzi explained.

The researchers hypothesized that treating patients with deep repetitive TMS would induce satiety and weight loss.

They enrolled 16 patients with a mean body mass index (BMI) of 34 and randomized them to receive high-frequency (18-Hz) TMS (treatment group, eight patients); low-frequency (1-Hz) TMS (control group, three patients); or sham treatment (five patients).

Low frequency (1-Hz) TMS suppresses cortical excitability, whereas high frequency (> 3 Hz) enhances it (so the 18-Hz group were expected to have enhanced dopamine release in response to food cues), Dr Luzi explained.

At baseline, after 5 weeks of treatment, and 1 month later, participants filled in a food craving questionnaire, had their weight recorded, and had blood drawn to determine metabolic parameters.

The TMS and sham sessions were given three times a week for 5 weeks. Before the TMS or sham sessions, participants were shown images of their favorite foods (cues). They received deep (H-coil) TMS that targeted the prefrontal cortex and insula bilaterally or sham treatment.

All patients received advice from a nutritionist and a physical-activity trainer every 2 weeks.

Significant Weight Loss After 5 Weeks of TMS Treatment

At 5 weeks, the patients who had received the high-frequency TMS had lost 4.5 kg and their food cravings were reduced by 34% — significantly greater than the changes in the other patients. These patients continued to lose weight, and a month later, they had lost 3.2% of their initial weight.

With the lifestyle-alone intervention, patients in the sham control group still lost 1.8% of their baseline weight, Dr Luzi noted.

At 5 weeks, patients in the high-frequency TMS group had significant reductions in blood levels of glucose, cholesterol, and cortisol and a significant increase in epinephrine, compared with their baseline values. These changes were not seen in the other participants.

"These findings support the role of repetitive TMS as a novel promising treatment for obesity," the researchers summarize.

If patients begin to regain lost weight or if their food cravings return, the procedure can be repeated for another few sessions, Dr Luzi noted.

Since TMS stimulates the same brain-reward center that is involved in other addictive behaviors (such as smoking or gambling), in theory, people who receive TMS treatments for obesity might also see a decrease in their other addictive habits, he speculated.

"The patients are incredibly happy" with this procedure, according to Dr Luzi.

"They love it. We have a line of patients; we are receiving phone calls....It's not a problem of compliance; they want to do it."

The researchers are continuing to investigate these patients for another 6 months.

Dr Luzi is on advisory panels for AstraZeneca and Johnson & Johnson and is a consultant for McKinsey & Company. He receives research support from the MOVI Group and is on speaker bureaus for Eli Lilly, Menarini Group, Novo Nordisk, Sigma-Tau, and Sunstar . The coauthors have no relevant financial relationships.

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American Diabetes Association 2016 Scientific Sessions; June 12, 2016; New Orleans, Louisiana. Abstract 266-OR

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