Treatment of Acute Mood Depressive Episode in Borderline Personality Disorder With rTMS

Inclusion Criteria: * Male or Female, between the ages of 18 and 80 at the time of screening. * Able to read, understand, and provide written, dated informed consent prior to screening. Proficiency in English sufficient to complete questionnaires / follow instructions during fMRI assessments and aiTBS interventions. Stated willingness to comply with all study procedures, including availability for the duration of the study, and to communicate with study personnel about adverse events and other clinically important information. * Diagnosed with Major Depressive Disorder (MDD) or Bipolar II, or unspecified depressive disorder AND Borderline Personality Disorder or trait, with a current Mood Depressive Episode (MDE), according to the criteria defined in the Diagnosis and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5). * MADRS score of ≥20 at screening (Visit 1). * TMS naive. * Access to ongoing psychiatric care before and after completion of the study. * Access to clinical rTMS after study completion. * In good general health, as evidenced by medical history. * For females of reproductive potential: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation. * Agreement to adhere to Lifestyle Considerations (see section 5.3) throughout study duration. Exclusion Criteria: * Pregnancy * The presence or diagnosis of prominent anxiety disorder, personality disorder, or dysthymia * Current severe insomnia (must sleep a minimum of 5 hours each night before stimulation) * Current mania or psychosis * Bipolar I Disorder and primary psychotic disorders. * Autism Spectrum disorder or Intellectual Disability * A diagnosis of obsessive-compulsive disorder (OCD) * Current moderate or severe substance use disorder or demonstrating signs of acute substance withdrawal. * Urine screening test positive for illicit substances. * Any history of ECT (greater than 8 sessions) without meeting responder criteria * Recent (during the current depressive episode) or concurrent use of a rapid acting antidepressant agent (i.e., ketamine or a course of ECT). * History of significant neurologic disease, including dementia, Parkinson's or Huntington's disease, brain tumor, unexpected seizure/epilepsy disorder, subdural hematoma, multiple sclerosis, or history of significant head trauma. * Untreated or insufficiently treated endocrine disorder. * Contraindications to receiving rTMS (e.g., metal in head, history of seizure, known brain lesion) * Contraindications to MRI (ferromagnetic metal in their body). * Any current or past history of any physical condition which in the investigator's opinion might put the subject at risk or interfere with study results interpretation. * Depth-adjusted aiTBS treatment dose \> 65% maximum stimulator output (MSO) * Treatment with another investigational drug or other intervention within the study period. * Any other condition deemed by the PI to interfere with the study or increase risk to the participant.