Depersonalization or loss of self is a feature to be expected on the path, in many Eastern traditions, but it's not the goal. It's an identity crisis that arises when the various ego layers are challenged and the relationship to true self must be re-evaluated. They espouse that there is a subtle-level self occurring that is underneath all the personality and ego layers that developed since birth. This "real self" is not in the beyond or 'over there' somewhere, it's always present, in every moment. It's who's doing the typing here, who's doing the reading. It's very basic. It's right here, right now. Your real, human level self is right there with you in every moment, you don’t have to go looking for it. In Daoism they call it the De, or Virtue, or your True Nature. Almost immediately after birth the conditioning begins and ego defenses develop, and after this it becomes harder and harder to find the De. But there is a structure-like presence that always permeates the ego and body and mind, and this presence is palpable, and human.
Hardly anyone ever finds their way home to this shining presence, but for me, this is the secret to human level happiness and peace. In a nutshell what I'm saying is that when the Absolute resonance takes the form of a human, a resonating "me" is created and this is the real self which our mind/bodies can experience and which allows for the body-based connection we all have lost and seek. But most of the time we don’t even notice it’s there due to the extraneous noise within ourselves.
I'm making it sound more esoteric than it actually is. A lot of spiritual seekers and drug users with a spiritual bent think that the objective is to obliterate the self. Following that path is what causes depersonalization in a useless way, because it divorces you from your own human experience. All you end up doing is forming a new, confused ego layer that is trying to be the Absolute but can't, which creates resistance to seeing the ever-presence De. The only way out of that is to return to the De, your true nature, who you really are and the true essence of your very human experience, which is unique to each person. You don't have to go anywhere to be at peace.
In other words, be who you are, nothing else is being demanded of you. "Self" is not what causes suffering. Attachment is what causes suffering, and the various ego layers which obscure the subtle self are all attachment based. Trauma can destroy the ego layers and awaken you to your true self, or it can create more ego layers which obscure the true self. It can go either way. The awakened version may or may not be permanent.