Repressed memory is a controversial, and largely scientifically discredited, claim that memories for traumatic events may be stored in the unconscious mind and blocked from normal conscious recall. As originally postulated by Sigmund Freud, repressed memory theory claims that although an individual may be unable to recall the memory, it may still affect the individual through subconscious influences on behavior and emotional responding.
Despite widespread belief in the phenomenon of repressed memories among laypersons and clinical psychologists, most research psychologists who study the psychology of memory dispute that repression ever occurs at all. While some psychologists claim that repressed memories can be recovered through psychotherapy (or may be recovered spontaneously, years or even decades after the event, when the repressed memory is triggered by a particular smell, taste, or other identifier related to the lost memory), experts in the psychology of memory argue that, rather than promoting the recovery of a real repressed memory, psychotherapy is more likely to contribute to the creation of false memories. According to the American Psychological Association, it is not possible to distinguish repressed memories from false ones without corroborating evidence.
In part because of the intense controversies that arose surrounding the concepts of repressed and recovered memories, many clinical psychologists stopped using those terms and instead adopted the term dissociative amnesia to refer to the purported processes whereby memories for traumatic events become inaccessible, and the term dissociative amnesia can be found in the DSM-V, where it is defined as an "inability to recall autobiographical information. This amnesia may be localized (i.e., an event or period of time), selective (i.e., a specific aspect of an event), or generalized (i.e., identity and life history)." The change in terminology, however, has not made belief in the phenomenon any less problematic according to experts in the field of memory. As Richard J. McNally, Professor and Director of Clinical Training in the Department of Psychology at Harvard University, has written: "The notion that traumatic events can be repressed and later recovered is the most pernicious bit of folklore ever to infect psychology and psychiatry. It has provided the theoretical basis for 'recovered memory therapy'—the worst catastrophe to befall the mental health field since the lobotomy era."