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

This study tests a new treatment for people with borderline personality disorder (BPD). The treatment combines a medication called D-cycloserine with one day of transcranial magnetic stimulation (TMS). The main questions it aims to answer are: * How many participants complete the treatment? * How do participants feel about the treatment? * Does the treatment have neurophysiological changes on participants? * Does the treatment improve BPD symptoms? * Do the benefits last over time? Participants will be asked to: * Come to the clinic for interviews and testing * Complete weekly questionnaires for 4 weeks before the treatment day * Take D-cycloserine the night before treatment * Attend one treatment day at the clinic. On that day, they may receive up to 20 short TMS sessions (each lasting 3 minutes and separated by 30 minutes). This visit may last up to 12 hours. * Complete weekly questionnaires for 6 weeks after the treatment day.