What Causes Borderline Personality Disorder (BPD)? Borderline Personality Disorder (BPD) is a complex and multifaceted mental health condition, and its exact causes are still not fully understood. However, research has identified a combination of genetic, biological, and environmental factors that likely contribute to the development of BPD. The interplay between these factors makes BPD unique in its onset and manifestation. This article will explore the various potential causes of BPD, helping to better understand why some individuals develop this disorder and others do not.