Inside The Borderline Mind – Insight For Non Borderlines

Inside the borderline mind there is a very profound split, fragmentation, and in some cases a shattering of the ego due to the narcissistic intrapsychic injury sustained at a very young age as the result of abandonment (actual and/or perceived) that arrests emotional development.
What does every family member, friend, relationship partner, or ex-relationship partner (non borderline) need to know about what goes on inside the borderline mind? Why does understanding the workings of the borderline mind matter to those who are non borderline?

Non Borderlines Trying to Understand Borderline Magical Thinking

What is Magical Thinking In BPD?
Magical thinking is essentially adhering to the (distorted) belief that thoughts can cause events. When someone with BPD is magically thinking and thoughts seem to cause events what is also often a part of this experience for the borderline is that what they feel becomes a fact to him or her in what is a distorted sense of “reality”.