Inclusion Criteria:  Current diagnosis of Gambling Disorder, based on the Diagnostic and Statistical Manual of Mental Disorder - Fifth Edition (DSM-5);  Exclusion Criteria:  Current or pre-existing DSM-5 diagnosis of schizophrenia, bipolar disorder, or other psychotic disorder; Use in the past 4 weeks of any medication with known pro-convulsant action, including antipsychotic medications, tricyclic antidepressants, and antihistamines drugs; Medical history with significant neurological disorder, including organic brain disease, epilepsy, stroke, brain lesions and multiple sclerosis, previous neurosurgery, or personal history of head trauma that resulted in loss of consciousness for > 5 minutes and retrograde amnesia for > 30 minutes; Any personal or family history (1st degree relatives) of seizures other than febrile childhood seizures; Any psychiatric, medical or social condition whether or not listed above, due to which, according to the judgment of the PI and after any consults if indicated, participation in the study is not in the best interest of the patient; For female patients: Pregnancy/breastfeeding.