For many smokers, quitting isn’t just a matter of motivation. It’s an internal battle between the brain that demands the reward and the brain that tries to maintain control, while tobacco causes more than 8 million deaths per year according to the World Health Organization. Faced with treatments from which less than one in ten smokers derive lasting benefit, an American team tested an unexpected approach: acting directly on these brain circuits.
At the Hollings Cancer Center at the Medical University of South Carolina, researchers used a targeted brain stimulationthere
repetitive transcranial magnetic stimulation (rTMS), to strengthen a key area of self-control, the dorsolateral prefrontal cortex
(DLPFC). Their essay, published in the Journal of Psychiatric Researchshows that in fifteen sessions, the participants smoked on average 11 fewer cigarettes per day than those receiving a placebo or stimulation of the reward circuit.
How stimulation of the prefrontal cortex reprograms the urge to smoke
The authors describe tobacco use disorder as a profound imbalance. “In addiction, brain systems can become imbalanced,” says Dr. Xingbao Li, principal investigator and associate professor in the Department of Psychiatry and Behavioral Sciences. “A system, linked to reward and the compelling need to consume, becomes hyperactive. Another, responsible for control and decision-making, weakens”. In short, the accelerator is stuck to the floor, the brake is worn…
To test whether it was possible to retrain this brake, researchers used a targeted brain stimulationthere repetitive transcranial magnetic stimulation (rTMS), to strengthen a key area of self-control, the dorsolateral prefrontal cortex
(DLPFC). At the Hollings Cancer Center at the Medical University of South Carolina, 46 smokers motivated to quit were randomly assigned to three groups: 10 Hz excitatory rTMS over the left DLPFC, 1 Hz inhibitory rTMS over the medial orbitofrontal cortex (mOFC), or sham session. They compared two approaches, each targeting a distinct brain circuit involved in smoking:
- Strengthen self-control by stimulating the dorsolateral prefrontal cortex (DLPFC), a brain region involved in decision-making and restraint;
- Attenuate reward signals by stimulating the medial orbitofrontal cortex (mOFC), a brain region linked to craving and reward.
Fifteen sessions were carried out over three weeks, guided by functional MRI and personalized electric field dosing. “C“is a form of precision medicine”said Professor Li. “We tailor the treatment to each person’s brain.”.
Targeted rTMS of the DLPFC: fewer cigarettes and a brain that reorganizes itself
The results are clear. The DLPFC group reduced their consumption by 11.14 cigarettes per day on average, compared to 6.43 for the placebo and 4.92 for the mOFC group. Cravings measured on several scales fell further, and exhaled carbon monoxide, a biological marker of smoking, fell by about 7 parts per million, compared with a much smaller reduction in the other groups. These effects persisted for at least a month after the end of the sessions.
Brain imaging sheds light on this change in behavior. After rTMS on the DLPFC, the activity of this control region increases, while that of the orbitofrontal cortex, linked to reward, decreases. The more the activation of the DLPFC progresses, the more the number of cigarettes per day decreases. “It’s a downward effect.”said Professor Li. “We strengthen the control system, and it naturally regulates the reward system.”. No serious adverse effects have been reported, mainly transient local pain.
For which smokers this targeted brain stimulation can help
At the Hollings Cancer Center, this track could be added to the smoking cessation program, which already offers support, medications and behavioral tools. rTMS does not replace these approaches but could offer an additional option to very dependent smokers, to those who cannot tolerate traditional treatments or to cancer patients who continue to smoke despite the urgency to quit. The technique is noninvasive and already approved by the Food and Drug Administration for depression, but this precision version remains under evaluation.
However, the study remains modest: 35 participants completed the protocol, and the trial was not designed to prove lasting abstinence. Larger trials are underway to confirm the results, adjust the duration of the treatments and better define which profiles benefit the most. For the moment, in France, only a few teams are exploring rTMS in addictions. Tobacco specialists point out that other means already exist to reinforce this “brain brake” without a machine, from cognitive therapies to concrete strategies for managing cravings, while waiting for these targeted stimulation techniques to become, perhaps, one more tool in the arsenal for quitting smoking.