I have had many traumas since childhood. During one of the earliest ones, I sectioned off that part of my life deep in my subconscious, including all memories of that time, interests I had, hobbies, friendships, etc. I just "walked away" from it all without knowing that's one happened. That was my first "split" of my personality.
I did the same thing with many other time periods in my life. Also, the skills I gained during those times, causing me to be unable to "access" that knowledge, skills, and memories I needed unless I "switched" to that part of my "fragmented self" and I didn't even know I was doing it, though I knew something was terribly wrong.
My fragments aren't whole personalities, just big defensive walls between memories. The first I really began to face that yes, I was injured this badly was when I switched in front of two therapists in DBT. They ratted me out to my CBT therapist, (ha!) and he very gently starting bringing my different mannerism to my attention. Then he began to intentionally poke at the triggers causing me to 'switch' while in therapy to help my fragments become more aware of each other. This also has allowed me to gain back a lot more of my life skills I picked up and employ them now without having to "switch."
It was frightening before I learned how to accept the reality of my psychological injury. I stopped blaming, shaming, or hating on myself for being this way. It helped me survive. It's just no longer necessary so I'm working on it.
Once my therapists saw me "switch" I qualified for a lot more help. I've had Dialectical-Behavioral Therapy to gain distress tolerance skills and resilience. I started seeing the trauma therapist, and started doing EMDR. I've had family counseling to help me function better at home.
I first got diagnosed in 2015. It's been a long haul, but I'm doing very well now. The EMDR especially was very helpful in lowering the walls between my traumas in my brain so the periods of amnesia have finally revealed the traumas I couldn't access, allowing me to deal with them.
It's hard, but my life is SO much better in so many ways. I feel fortunate that my brain knew how to protect me until I was strong and stable enough to begin healing this stuff.
Every trigger I have has turned out to be linked to a trauma. Once I gained enough distress tolerance skills to be able to "follow" where the triggers were trying to lead me, I could identify that trauma. That became targets in EMDR. After EMDR on traumas, they no longer feel present, and they don't intrude in my current life. They lose their ability to hijack my fight-or-flight/hyper-reactive responses, and recede into the past. They become just memories instead of minefields of pain and anguish.
I can't recommend therapy enough. I could absolutely not heal my "self" because I couldn't perceive all the fragments. It really does take a lot of talking and work to set those down. But oh my gosh, it feels so much better!