The goal of this clinical trial is to investigate the efficacy of theta burst stimulation in individuals with gambling disorder. The main goal is to compare the severity of gambling problems following 2 weeks of intervention between active group and sham group. Participants will be randomized into active and sham group. The severity of gambling problems are assessed by self-reported questionaires.

Gambling disorder, formerly known as pathological gambling, is a gambling behavior that causes significant function impairment in personal, social, occupational domains. Currently there is no pharmacological treatment for gambling disorder and it is urgent to develop innovative treatment modalities. Image studies have found a link between prefrontal circuit dysfunction and behavioral disinhibition, which supports the use of non-invasive brain stimulation as a potential treatment for gambling disorder. In this study, 75 patients with gambling disorder will be randomly assigned in a 2:1 ratio to the intervention group (50 patients) and the control group (25 patients) on double-blind basis. The study duration is 2 weeks, with 10 sessions of 20 minutes each. The intervention group will receive repetitive transcranial magnetic stimulation at the left dorsolateral prefrontal cortex and pre-supplementary motor area, while the control group will receive sham stimulation. The Chinese version of the Problem Gambling Severity Index (PGSI), the Gambling Symptom Assessment Scale (G-SAS), and the Visual Analogue Scale (VAS) for craving will be administered at week 0, 2, 4, 8, and the change in gambling severity between the two groups will be compared by repeated measures ANOVA.

Inclusion Criteria:

1. age between 18 and 65 years;
2. fulfilling at least 4 of the Diagnostic and Statistical Manual version 5 (DSM-5) criteria of gambling disorder for at least 12-month assessed by the Structured Clinical Interview

Exclusion Criteria:

1. Inability to provide informed consent or comprehend the study procedure;
2. A major psychiatric illness that required chronic psychotropic medication or inpatient treatment, including schizophrenia spectrum disorder, bipolar spectrum disorder, and major depressive disorder with psychotic features.
3. A current DSM-5 diagnosis of substance use disorder except nicotine use disorder or the use of one to two low-potency benzodiazepine tablets for sleep impairment;
4. Have known preexisting noise-induced hearing loss, concurrent treatment with ototoxic medications, or with cochlear implants.
5. Unstable medical illness, including malignancy, uncontrolled diabetes mellitus, unstable cardiac disease or recent myocardial infarction, or cerebrovascular or cardiovascular risk factors that require intensive medical management
6. On medications known to lower seizure threshold (e.g., TCA, bupropion, clozapine)
7. Implants controlled by physiological signals, including pacemaker, implantable cardioverter defibrillator, cochlear implant.
8. Metallic objects in the head, including stenting, suture.
9. Elevated risk of seizure due to traumatic brain history, seizure history, and head trauma, intracranial lesion, and alcohol or benzodiazepines withdrawal syndrome, stimulant intoxication.