I started to take the idea more seriously when
1.) I have read Peter A. Levine's book "Waking The Tiger". The book talks about past trauma being stuck in the nervous system, and how you can release it through a method he calls somatic experience. He writes about emotional pain / nervous system energy that is stuck in you because of the unresolved freeze response, and that he observed that many clients he had as a therapist, are scared to release the energy because they identify with it. He says they basically confuse "life energy" with the traumatic energy itself. They believe they ARE the trauma, and are scared to release it. To me, that beautifully explains why people get panic attacks. Their body wants to release the stuck energy, but they block it because they think the traumatic energy is them. It totally resonates with what I have felt and believed.
2.) Harris Harrington talks about self-esteem vs. self-worth, and that DPd people (also perfectionists, even if they don't have DP) think that if they feel bad, that means they ARE bad. If they make a mistake and feel bad, they think they just have been CRUSHED as a person. DPd people confuse the two. Self-esteem is something that SHOULD be effected by things that happen to you, your achievements, your failures, your status, money, etc.. But self-worth should never be. If you lose everything, if you get hurt, if you fail, anything happens, you should still know that you are still yourself, and you still have value, just by being who you are and by being a human being.
I think this 2 things are closely related. Both has to do with the belief that YOU are what you feel. If you think about it, why else would you say that you are "depersonalized", detached from yourself, while in reality, you just feel alien and strange feelings. Also explains why DPd people have so much thought about existence, soul, ego, etc.. They believe that they are what they feel. And if what they feel can change so drastically (panic attack, DP), then they may not even exist. Which is stupidity.
You are not what you feel, you are a unique human being, a unique soul that is unrepeatable.
You'll realize once you are brave enough to feel your pain. I have been through EXTREME feelings in recovery. More extreme than DP. While doing my work, I have felt through childhood traumas, for hours I have felt exactly like that little child who losted his brother while standing on those same stairs, felt like the kid who got bullied in school, my whole emotional world have been occupied with the past. Yet, I went home, and did my business, did what I had to do. Haven't lost myself. Opposite, felt more like myself.