Transcranial Magnetic Stimulation for Attention Deficit/Hyperactivity Disorder (ADHD)

Inclusion Criteria: Eligible participants will be: 1. Healthy males and females who are between 18 and 65 years of age with an ADHD diagnosis (meet diagnostic criteria for ADHD on the SCID-5 module for adult ADHD). 2. Planning to live in the area for at least the next 6 weeks; 3. Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the combined consent and HIPAA form; 4. Able to communicate fluently in English (speaking, writing, and reading). Exclusion Criteria: Subjects who present and/or self-report with the following criteria at any point during study participation will not be eligible to participate in the study: Alcohol/Drugs: 1. History or current diagnosis or treatment for alcohol or drug abuse (as reported during phone screen); 2. Positive breath alcohol concentration test (BrAC greater than or equal to 0.01) at intake; 3. A positive urine drug screen for cocaine, phencyclidine (PCP), amphetamines, methamphetamines, benzodiazepines, methadone, and/or barbiturates at Intake, Baseline, or Sessions 5, 10, 15 or 20. Medication: Current use or recent discontinuation (within the past 6 months at the time of Intake) of: 1. Gamma-Aminobutyric Acid (GABA)-ergic medications 2. Glutamatergic medications 3. Any medication for the treatment of ADHD 4. Benzodiazepines 5. Any medication that is known to lower the seizure threshold (e.g.,clozapine, bupropion, tramadol, carbapenems, stimulants) 6. Any medication that could compromise participant safety as determined by the Principal Investigator and/or Study Physician Current use or recent discontinuation (within the last 14 days at the time of Intake) of: 7. Anti-psychotic medications 8. Nicotine replacement therapy (NRT) Daily use of: 9. Opiate-containing medications for chronic pain Medical/Neuropsychiatric: 1. Women who are pregnant, planning a pregnancy, and/or breast feeding. 2. History of seizures, epilepsy, or history of epilepsy in first-degree relative 3. History of stroke or transient ischemic attack (warning stroke) 4. History of traumatic brain injury or self-report of brain or spinal tumor 5. History of head injury with unconsciousness lasting more than 5 minutes 6. Previous brain surgery 7. Any additional neurological condition that would likely reduce the safety of study participation, including central nervous system (CNS) vasculitis, intracranial tumor, intracranial aneurysm, multiple sclerosis or arteriovenous malformations 8. History of tinnitus 9. History of diabetes mellitus 10. History of atherosclerotic vascular disease 11. A medically unstable cardiopulmonary or metabolic disorder 12. Increased risk for myocardial infarction or other major cardiopulmonary complications. 13. Any uncorrected visual impairment or abnormality 14. Self-reported history, current diagnosis of psychosis or symptoms consistent with a mood disorder based upon the Structured Clinical Interview for DSM-5 (SCID); including schizophrenia, mania, bipolar disorder, an eating disorder, obsessive compulsive disorder, an anxiety disorder, major depression (subjects with a history of major depression but in remission for past 6 months are eligible). TMS-related: 1. Subjects with ferromagnetic material in or in close proximity to the head (with the exception of oral dental devices) 2. Implanted devices (including vagus nerve stimulator (VNS), deep brain stimulator (DBS), pacemakers, spinal cord stimulators, medication pumps, ventriculo peritoneal shunts, defibrillators, intracardiac lines) 3. Self-report of any skull fracture or opening 4. A disturbance in normal sleep patterns/sleep deprivation General Exclusion: 1. Any medical condition, illness, disorder, or concomitant medication that could compromise participant safety or treatment, or affect clinical or cognitive outcomes, as determined by the Principal Investigator 2. Inability to complete study tasks and provide quality data, as determined by the Principal Investigator 3. Low or borderline intellectual functioning - determined by a score of less than 90 on the Shipley Institute of Living Scale (SILS) (administered at Intake Visit). The SILS correlates with the Wechsler Adult Intelligence Scale-Revised (WAIS-R) Estimated Intelligence Quotient (IQ) Test 4. Inability to provide informed consent