There is something about the way we come to know ourselves that is at once obvious, yet also mysterious. Let's call it the principle of negativity: We learn about some things chiefly when we are lacking them, or losing them. Unnoticed in the state of orderly normalcy, such things become disturbingly evident in the state of disordered normalcy, or in other words, in the state of disorder.
The principle of negativity can be traced in the world of physical being: "I did not even think that I had a heart until my heart was broken." "I had no thoughts about my stomach until I was hit with an acute stomachache." The principle of negativity dominates in the sphere of mental life too. Depression burns with pain, despair, and longing for the mental ease of the nondepressed state of mind. The experience of depression brings the knowledge of the "joy of life" that was almost "unnoticed"---though actively experienced-during the period preceding depression. The disordered state of depression illuminates the meaning of the orderly state of a normal mood. Paradise must be lost to be appreciated as paradise.
In the case of depersonalization, the principle of negativity often comes as an amalgam of insight into one's own personalization and stroke of losing this personalization. An individual learns about his or her personhood while suffering the loss of this personhood. One of my first patients, an exceptionally bright 15-year-old boy, recalled the prelude of his depersonalization. "I began to feel some vague, but uncomfortable, feeling of incompleteness. One morning I was walking from my home to school. A light 15-minute walk turned into an intense quest. It felt as if I had lost something. I went through all the little things I had to bring to school, other belongings, and things at home. Everything seemed to be in place. But something felt so disturbingly lost. Suddenly I realized, 'What I've lost is my self.' I discovered that I used to have a self and that now I have lost it. It felt like a very scary discovery. I learned about myself through the feeling that I am not myself anymore."
People with acute onsets of depersonalization in many instances undergo such an overwhelming identity crisis that they cannot conceptualize, formulate, or describe their experiences of losing their "self." Unbearable fear and avalanching anxiety urge them to seek immediate help, sometimes rushing to the ER. Typically, being in a health care facility provides a feeling of protection and reduces panic and catastrophic thinking, although the central depersonalization experiences are seldom addressed or understood by psychiatric ER doctors, many of whom do not understand or recognize depersonalization disorder.
Depersonalization comes as feeling of a loss of "my self," shaking the core of personhood and undermining the very ground of existence. Personalization could be compared with breathing. While I run, read, swim, or play, I am unaware of the primary activity of breathing, but rather focus on these "secondary" activities. When there is not enough oxygen in the air or something is wrong with my ability to breathe, only then do I become alarmingly aware of my primary activity of breathing.
Similarly, as far as my primary feeling of being myself (the "I am myself" feeling) is intact (in order), I am actually unaware of this feeling. I neither acknowledge nor care that there is a feeling "I am myself." I just feel habitually normal, "thoughtlessly" focusing on different secondary activities such as seeing, hearing, touching, dreaming, and thinking. I do not feel frightening confusion, nor struggle with the sensation that my thoughts are mechanical and strange, as if they were not mine. I do not question myself: "Who is the I seeing this flower?" The feeling of being myself stands behind me, supporting my way through life like the submerged part of an iceberg. It is invisible, hidden under the water, but it keeps the iceberg intact, provides its ability to float, resist weather, and so on. While I walk through the normal stream of life, this primary feeling "I am myself" forms a foundation for all my secondary activities, remaining "invisible" itself. The onset of depersonalization reveals the feeling of being myself through the painful experience of losing this feeling, or not feeling myself.
Before depersonalization, I had the feeling of being myself, but I was unaware of this feeling: I did not know that I felt that I was myself. In this sense, depersonalization comes like an insight of personalization in a negative form. Experience of paradise lost leads me to realize that I was in paradise, but am not there anymore. The experience of depersonalization---feeling "I am not myself"---leads me to realize that I had experienced personalization, or a feeling that I am myself.