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Dissociative amnesia is a diagnosis category that implies a proposed mechanism (often called dissociation) by which amnesia is caused by psychogenic means, such as trauma, and that amnesia is reversible later. Dissociative amnesia is listed in some of the most influential diagnostic manuals. Authors have noted the similarities in definition to repressed memories. Dissociative amnesia is a disputed category and phenomenon, and here I discuss the plausibility that this cognitive mechanism evolved. I discuss some general conditions by which cognitive functions will evolve, that is, the relatively continuous adaptive pressure by which a cognitive ability would clearly be adaptive if variation produced it. I discuss how adaptive gene mutations typically spread from one individual to the whole species. The article also discusses a few hypothetical scenarios and several types of trauma, to examine the likely adaptive benefits of blocking out memories of trauma, or not. I conclude that it is unlikely that dissociative amnesia evolved, and invite further development of these ideas and scenarios by others. Dissociative amnesia is a presumed memory phenomenon involving the storage of traumatic experiences, followed by a period of no conscious awareness, with later recall possible. It is also a diagnostic category in the influential Diagnostic and Statistical Manual of Mental Disorders. This current paper questions whether this extraordinary type of memory mechanism could have evolved in humans, by examining several different scenarios. The article is unable to identify a plausible consistent advantage that would have led to dissociative amnesia genes to spread throughout a population. [ABSTRACT FROM AUTHOR]

This article discusses the possibility of practitioners who mistake organic memory loss for dissociative amnesia. It starts with the case of a young man with complete retrograde amnesia due to a traumatic head injury. Because he did not show any gross neurological abnormalities, a neurologist thought his amnesia had a psychological origin. An extensive neuropsychological examination revealed that the man did have an organic reason for his amnesia. Next, the existence of dissociative memory loss as well as isolated organic retrograde amnesia is considered. While cases of organic memory loss are well‐documented, there is hardly any evidence for dissociative amnesia. It is argued that organic memory loss might be mistakenly taken for dissociative amnesia. In line with the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, practitioners are advised to rule out the possibility of organic memory loss, before diagnosing a patient with dissociative amnesia. A patient with autobiographical memory loss but without gross neurological abnormalities may be diagnosed with dissociative amnesia, i.e., amnesia with a psychological origin. In this article, I argue that the absence of apparent neurological symptoms does not mean that a patient's amnesia is caused by psychological factors. Only when a medical history, neuropsychological testing, and brain scans rule out a neurological origin of the memory loss, a patient may genuinely suffer from dissociative amnesia. [ABSTRACT FROM AUTHOR]

The controversy over alleged repressed and recovered memories of childhood sexual abuse (CSA) was among the most contentious ever to embroil psychology and psychiatry. Adapting paradigms from cognitive psychology, my research group tested hypotheses pertinent to repressed memory and false memory interpretations of recovered memories. We tested adults who: (1) report recovering memories of CSA after not having thought about their abuse for years; (2) report never having forgotten their CSA; (3) believe they harbor "repressed" memories of CSA; and (4) deny having been sexually abused. We tested hypotheses about mechanisms that might figure in the inability to recall memories of one's abuse and those that might render one susceptible to developing false memories of abuse. The purpose of this article is to summarize this work. Finally, I draw on the work of Lionel Penrose to speculate about why the popularity of the concept of repressed memories of trauma—or its synonym, dissociative amnesia for trauma—may be rising today. Experimental cognitive psychology research has failed to support claims that people possess the capacity to repress memories of trauma. Lionel Penrose's viral model of "fads" may explain the persistence (or resurgence) in belief in repression. [ABSTRACT FROM AUTHOR]