Written by Ph.D. O.v.h.Hart
The DSM-IV  refers to possible degrees of complexity in the presentation of dissociative amnesia, defining it as a dissociative disorder in its own right and as a symptom of more complex dissociative disorders. The DSM-IV defines the negative dissociative symptom (or disorder) of dissociative amnesia as “one or more episodes of inability to recall important personal information, usually of a traumatic or stressful nature, that is too extensive to be explained by ordinary forgetfulness” [7, p. 481].
This definition contains a number of inaccuracies and inadequacies, including being overly abstract, vague , nonspecific, incomplete . For instance, it gives clinicians no concrete signs or symptoms with which to determine the presence of amnesia; it omits any mention of the essential feature of dissociative amnesia, i.e., its reversibility. The inclusion of the expression “too extensive” is problematic: there can be many instances of dissociative amnesia with regard to brief periods of time—for instance, during the most threatening moments of traumatic experiences. And in patients with DID, most episodes of amnesia do not directly involve traumatic experiences, but rather apparently mundane actions such as buying something or writing something .
Adopting Pierre Janet’s categorization of dissociative amnesia , the DSM-IV  distinguishes the following types (see also [6,8,10,11]): localized amnesia; generalized amnesia; continuous amnesia; systematized amnesia; and, not mentioned by Janet, selective amnesia. Localized amnesia pertains to the inability to recall all events that occurred during a circumscribed period of time. A basic example would be amnesia for a specific traumatizing event such as a violent rape; Janet  reports a young woman’s amnesia for the death of her mother that she witnessed. Generalized amnesia consists in the failure to recall encompasses the person’s entire life. This type of dissociative amnesia may occur in various degrees of severity. In some cases, it seems that the patient has to learn over again all that she or he had learned before and doesn’t seem to recognize his or her partner and family members [13,14]. Continuous amnesia, the inability to recall events subsequent to a specific time to and including the present, is rarely diagnosed. Neurological factors might be involved . Systematized amnesia pertains to the loss of memory for certain categories of information. For instance, the patient is amnesic for everything that related to her or his family. Janet  mentioned a woman who, after confinement, forgot not only the birth of her child, but also the facts connected with it. Selective amnesia, finally, pertains to the inability to recall some, but not all, of the events during a circumscribed period of time. On a micro-scale this might, for instance, pertain to remembering a rape, but not the most threatening part of it, i.e., the pathogenic kernel  or “hot spot” . The existence of this pathogenic kernel also may have caused amnesia to develop for the entire event; the resolution of this kernel then is essential in the recovery of the memory .