Psychology Today | 02.04.2026 03:26
I have been treating clients for borderline personality disorder for more than 45 years. When I first started studying the topic, most theorists emphasized the role early abandonment trauma played in its development. A great deal of research focused on 14 to 24 months as a critical window when normal personality development could be derailed, and borderline personality disorder could develop instead (Mahler, Pine, and Bergman, 1975).
