Optimization of NIBS for Treatment of Addiction

Inclusion Criteria Participants must meet all of the following: * Provide informed consent * Age 18-85 years * Diagnosis of opioid use disorder (DSM-5) with ongoing non-prescription opioid use confirmed by self-report and urine toxicology * Report current opioid craving * Enrolled in a certified Opioid Treatment Program and receiving methadone maintenance treatment * Stable methadone dose prior to enrollment * Reside locally with no plans to relocate during the study Exclusion Criteria Participants will be excluded if they: * Are pregnant * Have frequent illicit stimulant use or acute stimulant intoxication * Are using substances or medications that may interfere with study assessments (e.g., stimulant medications, buprenorphine-based therapies, naltrexone) * Have significant neurological conditions (e.g., stroke, epilepsy, brain tumor), abnormal EEG findings, history of brain surgery, significant head injury, or unexplained syncope * Have contraindications to noninvasive brain stimulation (e.g., metal in the head, implanted brain devices) * Have moderate to severe depression or active suicidal ideation/behavior * Have active malignancy * Consume substances that could confound opioid toxicology results (e.g., poppy-seed products)