An 18-Month Psychotherapy of Borderline Personality Disorder

The purpose of the study is to examine the impact of an 18-month psychotherapy treatment for borderline personality disorder. The investigators will examine changes in psychosocial and work functioning in patients with borderline personality disorder using an 18-month psychotherapeutic treatment. The investigators are recruiting female patients between the ages of 18-35 who meet DSM criteria for BPD. The investigators are excluding patients who meet the following criteria: * psychotic disorders * a current major depressive episode * bipolar I disorder * current substance dependence * antisocial personality disorder. * unable to undergo 18-months of twice weekly psychotherapy in NYC (due to the COVID19 pandemic in person meetings are suspended (see detailed description) but will be restated once this is considered safe again) Participants in the study will receive 18-months of twice weekly psychotherapy, free of charge, as well as compensation for follow-up assessments. They may be currently taking psychiatric medication. Participants will be assessed using semi-structured diagnostic interviews, self-report instruments, and computerized tasks in an initial assessment session lasting about 6-8 hours. They will also be assessed using computerized tasks. Follow-up assessments will occur throughout the treatment as well as after the treatment, lasting about 1-4 hours. The investigators will also be collecting information on their treatment history and psychiatric medication as part of the study.