A Pilot Trial of One-Day Accelerated TMS and D-cycloserine in Suicidal Patients With Borderline Personality Disorder

Inclusion Criteria: * Adult (18+) of any gender * Meets DSM-5 criteria for BPD, per assessment with the Structured Clinic Interview for DSM-5 Personality Disorders (SCID-5-PD), BPD Module * Moderate to severe SI during the two weeks prior to screening, as indexed by a score of 9 or higher on the Modified Scale for Suicide Ideation - Self Report (Clum \& Yang, 1995) Exclusion Criteria: * Current manic or hypomanic symptoms, as assessed by the Diagnostic Assessment Research Tool (DART) screener and diagnostic modules, where relevant. * Current clinically significant psychotic symptoms not better accounted for by BPD, as assessed by the DART psychotic symptoms screener. * Current alcohol or substance use disorder, that in the opinion of a study PIs, is of sufficient severity to impede engagement in treatment or is associated with significant risk of medical withdrawal, as assessed by the DART. * Medical documentation or self-report of current anorexia nervosa, bulimia nervosa, or eating disorder not otherwise specified - atypical anorexia nervosa or atypical bulimia nervosa, that is in the opinion of a study PIs is of sufficient severity to be associated with significant medical risks * Acute suicide risk, sufficient to require immediate hospitalization; * history of traumatic brain injury (TBI) or concussion involving loss of consciousness or amnesia for ≥24 hours; * any significant neurological disorder likely to be associated with increased intracranial pressure or cognitive impairment (e.g., epilepsy; Parkinson's disease); * diagnosed neurodevelopmental disorder (e.g., autism, downs syndrome; Ehlers-Danlos Syndrome) other than attention-deficit hyperactivity disorder (ADHD) or dyslexia * current diagnosis of delirium or dementia; * cognitive disorder secondary to a general medical condition * Pregnant and breastfeeding people are excluded in line with the studies our protocol is based upon using DCS and aTMS. Assessment of pregnancy will be completed during the 1-week prior to the administration of DCS (i.e., taken the night before TMS treatment), where relevant and according to MGB IRB policy. * Participants with contraindications to TMS (e.g., metal in head or neck area), or at increased risk for adverse events (e.g., seizure history or markedly heightened risk factors for seizures, serious medical problems, implanted devices) will be excluded. * Participants with a known allergy to DCS will be excluded from the study. * No patients with involuntary hospitalization status will be recruited for the study. * No individuals who are not proficient in English will be recruited for the study * Subject does not have a PCP