DLPFC rTMS is more effective than sham or orbitofrontal stimulation for smoking cessation and alters frontal brain activity: A double-blind, sham-controlled randomized clinical trial.

OBJECTIVE

Repetitive transcranial magnetic stimulation (rTMS) shows promise for smoking cessation, but its neural mechanisms remain unclear. It is unknown whether rTMS reduces smoking by enhancing executive control or suppressing reward-related brain activity. This study aimed to address this gap by comparing excitatory and inhibitory rTMS targeting distinct cortical circuits implicated in tobacco use disorder (TUD).

METHODS

In a double-blind, sham-controlled design, treatment-seeking individuals with TUD were randomized to 15 sessions of personalized, fMRI-guided, E-field-dosed rTMS: (1) sham rTMS, (2) excitatory 10 Hz rTMS over the left dorsolateral prefrontal cortex (L-DLPFC; 3000 pulses/session), or (3) inhibitory 1 Hz rTMS over the left medial orbitofrontal cortex (L-mOFC; 900 pulses/session). fMRI scans were conducted pre- and post- 15 sessions of rTMS. Primary outcomes were reductions in cigarettes per day (CPD) and changes in blood-oxygen-level-dependent (BOLD) activity.

RESULTS

Thirty-five of 46 participants completed the study (sham = 9; 10 Hz L-DLPFC = 12; 1 Hz L-mOFC = 14). The 10 Hz L-DLPFC group showed a significantly greater CPD reduction than 1 Hz L-mOFC and sham (-11.14 vs. -4.92 and -6.43, respectively; p < 0.0001, partial η2 = 0.135). rTMS to the L-DLPFC also increased prefrontal activity and decreased orbitofrontal activity (p < 0.05), with the degrees of CPD reduction correlating with enhanced activation in L-DLPFC (p < 0.05).

CONCLUSIONS

Enhancing executive control via 10 Hz rTMS over the L-DLPFC was more effective for smoking reduction than suppressing reward circuitry with 1 Hz rTMS over the L-mOFC. Findings suggest that strengthening prefrontal regulation of reward processing is a key mechanism by which rTMS promotes smoking cessation.

TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT04903028.