I am pulling from several sites to explain/describe DA and I am adding my personal commentary to explain how I experience it. I am also underlining things that relate to me, personally.
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Dissociative amnesia is a condition in which a person becomes unable to remember events from a part of their life. It affects about one percent to three percent of people in the general population and has a few main forms that have different effects. Generally, people with dissociative amnesia remember new facts and how to perform daily activities. (Today is not the problem.)
Symptoms include memory loss that can vary in severity from details to entire gaps of time. (I am partially amnesic and only remember pieces of my childhood. I also can count on one hand the memories I have of my younger sister although we lived together for 10 years and I even have photos I took of her. I only remember her clearly after I moved out.) It also can result in a struggle with one’s identity, as well as experiencing a bewildered state of wandering, called a dissociative fugue. (I have not experienced fugue.)
The specific cause of dissociative amnesia is unknown but is strongly linked with having experienced some form of psychological trauma, especially as a child. Factors contributing to the development of dissociative amnesia include:
- Having a genetic predisposition: This may lead to the development of dissociative amnesia in some people. An example of a possible genetic influence is a variant in a gene involved with the neurotransmitter serotonin, which is involved in certain psychiatric disorders such as depression and anxiety.
- Having experienced psychological trauma: This is strongly associated with developing dissociative amnesia. Examples include childhood physical or sexual abuse, adult sexual assault, military combat, experiencing a natural disaster, or being subjected to torture. Repeated episodes of trauma, trauma of a longer duration, and trauma at an earlier age are all associated with a greater risk of developing dissociative amnesia. (I can add to the list of types of traumas mentioned here. As I have shared many times, I am a walking miracle. I am not supposed to be functioning or even alive. They had other plans for me.)
People with dissociative amnesia may not always regain their memories with treatment or may regain only some of their memories. In some cases, the person may not want to regain their memories, such as if the memories are from a painful event. (I have had enough recall to know at least some of what is behind that veil.)
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Another way to explain it:
There are three types, or patterns, of dissociative amnesia:
- Localized: Memory loss affects specific areas of knowledge or parts of a person’s life, such as a certain period during childhood, or anything about a friend or coworker. (My sister in the same house.) Often the memory loss focuses on a specific trauma. For example, a crime victim may have no memory of being robbed at gunpoint, but can recall details from the rest of that day.
- Generalized: Memory loss affects major parts of a person’s life and/or identity, such as a being unable to recognize your name, job, family and friends. (On very rare occasions, I have had moments of confusion about current self/situation. But those are rare and very momentary. I always get right back on track. It has not effected my job.)
- Fugue: With dissociative fugue, the person has generalized amnesia and adopts a new identity. For example, one middle manager was passed over for promotion. He did not come home from work and was reported as missing by his family. He was found a week later, 600 miles away, living under a different name, working as a short-order cook. When found by the police, he could not recognize any family member, friend or coworker, and he could not say who he was or explain his lack of identification. (Again, not me. I have never experienced fugue.)
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My main experience with this is being partially amnesic about my sister and about my growing up. The abuse is very buried. I have had some memory recall about it, but a whole lot of it is still behind the veil of amnesia.