Diseases and Disorders

Psychogenic Amnesia

Alexander Skvortsov


Introduction    

Amnesia, or “a condition in which a person is unable to remember things because of brain injury, shock, or illness”{1} is among the most common cause of memory loss, worldwide. This condition includes several distinct types of memory loss, including anterograde amnesia, or inability t0 form long term memories , retrograde amnesia, or loss of memories before a certain occurrence, post-traumatic amnesia, or generally transient amnesia occurring after a physical traumatic injury to the head, and psychogenic amnesia, which, unlike the other three major types of amnesia, which are generally caused by physical trauma, drugs, is caused by psychological reasons. Psychogenic Amnesia is a condition in which a patient is unable to recall autobiographical information,  which is usually traumatic [2]. Dissociative amnesia occurs in two versions: global and situation-specific, and can include several phenomena such as repressed memories and dissociative fugue.

 

Cause

    The primary difference between Psychogenic Amnesia and organic amnesias lies within the cause. Organic amnesia is triggered by physical damage to the brain, particularly the medial temporal lobe. This damage can stem from a impact, a chemical reaction, a disease, a botched surgery, or any other physical cause. Psychogenic Amnesia, on the other hand is a result of a non physical factor, usually severe stress. Stress can stem from many sources, including abuse, trauma, war, disasters, failed relationships, or other traumatic events. Psychogenic Amnesia is often accompanied by psychological trauma , often appearing alongside trauma-based diseases such as PTSD [2].

 

Overview

    Also known as Dissociative Amnesia or Functional Amnesia, Psychogenic Amnesia is a memory disorder characterized by a combination of retrograde and anterograde loss of memory [3]. In all types of Psychogenic Amnesia, the primary type of memory affected is episodic memory- memory about one’s identity. There are two general categories of Psychogenic Amnesia: Global Psychogenic Amnesia and Situation-Specific Amnesia.

    Situation-Specific Amnesia is a collective term used to describe Psychogenic Amnesias related to, caused by, or centered around specific event or timeframes. It is often linked to stressful events, and can be a part of Post-Traumatic Stress Disorder. This subtype of Psychogenic Amnesia is the most common category of this amnesia and includes several distinct patterns of memory loss.

    Localized Amnesia is a situation-specific amnesia which entails a total loss of recall for a contained period of time, ranging from several hours to several months to several years. This forgotten period generally follows a traumatic event. Localized amnesia is the most common form of psychogenic amnesia[2], which is why situation-specific amnesia is also the most common. Localized Amnesia goes hand in hand with an extremely similar amnesial pattern known as Selective Amnesia. Like Localized Amnesia, Selective Amnesia generally follows a traumatic or stressful event, and lasts for a circumscribed period of time, which generally lasts from several hours to several years. However, unlike Localized Amnesia, individuals experiencing selective amnesia will have some limited memories remaining from the given time period. Note that Selective Amnesia differs from natural forgetting, as the memory loss will be brought on by severe stress, trauma, or some other psychological cause. Selective Amnesia and Localized amnesia can occur side by side, one after the other, or intertwined.

    Systematized Amnesia is another subtype of situation-specific amnesia that differs from the Selective and Localized variants in that it is not limited to a time period.  Systematized Amnesia refers to the loss of all memory in a specific category. This can concern an entity, such as a person or a location, a smell or taste, or a type of object. However, since most dissociative amnesias stem from trauma or stress, the category of information that will be lost will most often relate to the situation that originally caused the stress or trauma.

    Continuous Amnesia is the final pattern of situation-specific memory loss, and differs substantially from the rest. Unlike all other psychogenic amnesial patterns, which are mainly characterized by loss of memory before, around, or shortly after the traumatic event, Continuous Amnesia works in an anterograde pattern, meaning that there is a loss of ability to create memory after the triggering event.

    In addition to those broad subtypes, situation-specific amnesia includes several special cases. In many cases of assault, the offender will claim, during legal proceedings, to be forgetful of the incident. Most of these claims tend to be dubious, although some may have truth in them. Studies find that true amnesia for an offense can occur either through substance use, notably that of alcohol, or when the offender is feeling passionate about his actions[5]. Another major phenomena associated with situation-specific amnesia is the idea of memory repression. Memory Repression is a process in which a memory is forgotten for a long period of time, generally several years, and then resurfaces. Most examples of alleged memory repression concern incidents in one’s childhood. The validity of repressed memories is highly contested and controversial, especially where legal matters are concerned. For example, Harrison G Pope of the Royal College of Psychiatrists published an article in 1998 strongly advising against the use of psychotherapy to discover repressed memories, as the process can result in the creation of false memories, which can then lead to false allegations, creating legal trouble. In his article,  Dr. Pope states that validity of repressed memories can not be proved [7]. In addition to that, in a Harvard Magazine article concerning Dr. Pope’s work, it is stated that he was unable to find any cultural examples of memory repression before 1786, suggesting that the idea of memory repression may be much more cultural than it is scientific [8].

    In addition to being an amnesia, Psychogenic Amnesia is also classified as a dissociative disorder by the DSM-V (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition) [2]. dissociative disorders are a category of disorders in which the patient loses some contact with their identity, consciousness, or sense of self, which ties in with the primary symptom of Psychogenic Amnesia, namely losing memory about oneself. This aspect of Psychogenic Amnesia is prominent in the global amnesia classification. Global amnesia, or generalized amnesia, is the second category of Psychogenic Amnesia, is much less common than situation-specific amnesias, and is a more complete amnesia. Memory loss during global amnesia can span an individual’s whole life, and can be semantic or procedural alongside the usual episodic memory loss. This memory loss is primarily of a retrograde nature, and can include loss of personal identity, ability to do tasks, or general information [2]. A more extreme case of global amnesia is generally categorized as a Psychogenic Fugue, or a total loss of personal identity. Individuals suffering through a psychogenic fugue often establish a new identity, wander, or otherwise function separate from their forgotten identity [5]

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    Psychogenic Amnesias are, in general, very interesting to neuroscientists as they serve as an example of how psychological trauma can affect the process of memory. While there is currently no cure, a therapist can treat psychogenic amnesia to attempt to make it less severe.


References


  1. Pettus, A. (2008, January 1). Repressed memory. Harvard Magazine. Retrieved from http://harvardmagazine.com/2008/01/repressed-memory.html.

  2. Pope, H. G. (1998). Recovered memories of childhood sexual abuse. BMJ : British Medical Journal, 316(7130), 488–489.l.

  3. McKay, G. C. M., & Kopelman, M. D. (2009). Psychogenic amnesia: When memory complaints are medically unexplained. Advances in Psychiatric Treatment, 15(2), 152–158. doi:10.1192/apt.bp.105.001586

  4. Dissociative Amnesia. (1995). Retrieved August 8, 2016, from Cleveland Clinic, http://my.clevelandclinic.org/services/neurological_institute/center-for-behavioral-health/disease-conditions/hic-dissociative-amnesia.

  5. Mastin, L. (2010). Psychogenic Amnesia - memory disorders - the human memory. Retrieved August 8, 2016, from Human Memory, http://www.human-memory.net/disorders_psychogenic.html.

  6. American Psychiatric Association. (2013). Dissociative Dissorders. In Diagnostic and statistical manual of mental disorders (5th ed.). doi:10.1176/appi.books.9781585624836.

  7. Amnesia. 2016. In Merriam-Webster.com. Retrieved August 8, 2016, from http://www.merriam-webster.com/dictionary/amnesia.

Alexander Skvortsov

Alexander Skvortsov


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