A study of individuals with tobacco use disorder in China reported that a five-day course of repetitive transcranial magnetic stimulation restructured the neural circuits associated with the disorder. It also significantly reduced participants’ smoking cravings. The research was published in the Journal of Affective Disorders.
Tobacco use disorder is a condition in which a person becomes dependent on nicotine and continues using tobacco despite its harmful effects. It is characterized by cravings, difficulty quitting, and withdrawal symptoms such as irritability, anxiety, and increased appetite. Long-term tobacco use increases the risk of serious health problems, including lung disease, heart disease, and cancer. Nicotine addiction alters brain chemistry, making it difficult to quit even when a person wants to stop. Social and environmental factors, such as peer influence and stress, can contribute to tobacco addiction.
Mainstream treatments include nicotine replacement therapy, medications, and psychotherapy. However, these treatments are not highly effective. For example, a 2013 study showed that even the most effective method—varenicline medication—only resulted in 27% of patients remaining smoke-free six months after their cessation attempt.
Study author Shuang Li and his colleagues sought to explore the differences in dynamic neural networks between individuals with tobacco use disorder and healthy individuals. They also investigated whether features of these dynamic networks changed after a five-day course of repetitive transcranial magnetic stimulation applied to the left dorsolateral prefrontal cortex in individuals with tobacco use disorder.
The study included 60 individuals with tobacco use disorder and 64 nonsmoking healthy individuals. Participants with tobacco use disorder were required to express a strong inclination to quit in order to be included in the study. Only those who answered “very likely” or “somewhat likely” on a motivation questionnaire were selected.
All study participants underwent functional magnetic resonance imaging (fMRI) of their brains. Participants with tobacco use disorder were then divided into two groups. One group underwent five days of repetitive transcranial magnetic stimulation using a Magstim Super Rapid2 device (Magstim Co., Whitland, United Kingdom). Repetitive transcranial magnetic stimulation is a noninvasive procedure that uses magnetic pulses to stimulate specific brain regions.
The study authors determined the intensity of stimulation by placing the coil of the magnetic stimulation device at a 45-degree angle above the area of the skull corresponding to the motor cortex. They adjusted the amplitude of the magnetic pulses to find the minimum intensity level that consistently elicited thumb or hand movements in at least five out of 10 consecutive trials. After this calibration, the stimulation was applied to the left dorsolateral prefrontal cortex of the participant’s brain.
The other group served as a sham control. In this group, the magnetic stimulation machine was positioned vertically at the target site and activated to ensure that participants believed they were receiving stimulation, although no actual stimulation was administered.
Results showed that, compared to nonsmokers, participants with tobacco use disorder exhibited increased functional connectivity between the frontoparietal network and the basal ganglia networks in the brain, as well as increased functional connectivity between the medial frontal network and the frontoparietal network.
Repetitive transcranial magnetic stimulation reduced the functional connectivity between the frontoparietal network and the basal ganglia network, while the functioning of the frontoparietal network became more independent and efficient (as indicated by an increased recruitment coefficient). Participants who received repetitive transcranial magnetic stimulation also experienced reduced smoking cravings.
“In summary, rTMS [repetitive transcranial magnetic stimulation] targeting the left DLPFC [dorsolateral prefrontal cortex] has the potential to serve as an efficacious tool for smoking cessation by reshaping executive and reward networks,” the study authors concluded.
The study highlights the potential of repetitive transcranial magnetic stimulation as a treatment for tobacco use disorder. However, it was conducted on a limited sample of young male smokers. Findings may differ for older smokers and female smokers with a more extensive history of smoking.
The paper, “Repetitive transcranial magnetic stimulation reshaped the dynamic reconfiguration of the executive and reward networks in individuals with tobacco use disorder,” was authored by Shuang Li, ZhengJie Zhang, Anhang Jiang, Xuefeng Ma, Min Wang, Haosen Ni, Bo Yang, Yanbin Zheng, Lingxiao Wang, and Guang-Heng Dong.
