David Van Nuys, Ph.D. Updated: Feb 27th 2009
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In this edition of the Wise Counsel Podcast, Dr. Van Nuys interviews John Kihlstrom, Ph.D. about Hypnosis, Dissociation and the Dissociative Disorders. Dr. Kihlstrom is a clinical psychology researcher and professor at UC Berkeley who is well known for his experimental work concerning dissociation. He first became interested in hypnosis as an undergraduate student at the University of Pennsylvania where he assisted researcher Martin Orne with the development of a hypnotic susceptibility questionnaire designed to predict people’s different experiences of hypnosis. As he became professionally involved in clinical research, his interest shifted towards the dissociative disorders; clinically significant conditions characterized by memory and identity problems that result from dissociation. Hypnosis and the dissociative process that unifies the dissociative disorders are similar if not identical mental processes, so Dr. Kihlstrom’s interest in dissociation was a natural extension of his original interest in hypnosis.
In the simple terms, to dissociate means to “space out” or to go into a trance (like a hypnotic trance). When this occurs, the normal and continuous flow of a person’s memories and experience gets altered. How memory becomes altered depends on the intensity of the dissociation taking place. Very mild forms of dissociation involve nothing more than losing a train of thought as in normal “spacing out”. More involved forms of dissociation can involve memory loss, known technically as “amnesia”. In the most severe cases of dissociation, a persons’ identity or sense of self becomes altered. A smooth and continuous identity depends on access to an unbroken record of experiential memories, so when memory becomes very broken up, so too can identity.
The DSM recognizes four types of dissociative disorders. These are, in descending order of severity (with the most severe first), Dissociative Identity Disorder (DID; formerly Multiple Personality Disorder), Dissociative Fugue, Dissociative Amnesia, and Depersonalization Disorder. The more severe dissociative disorders, exemplified by Dissociative Identity Disorder have captured the public’s imagination in popular film depictions such as the “Three Faces of Eve”, “Sybil” and more recently, “The United States of Tara“. Despite the fact that the best available evidence suggests these conditions occur rarely, since the 1970s and 80s numerous therapists have reported treating many severely dissociative patients. Many people frequenting online mental health community support websites also claim to have severe dissociative disorders like DID, leading some people to think that these disorders (or at least DID) occur far more commonly than researchers recognize.
Dr. Kihlstrom suggests that the dissociative disorders’ popularity has to do with their having “romantic” (e.g., tragic and dramatic and even mythic) qualities and because they force us to confront fundamental and fascinating questions about the nature of identity. He is skeptical about the notion that the dissociative disorders are common, however. Kihlstrom acknowledges that the incidence rate of reported cases of dissociative disorder reported has skyrocketed in recent decades, but is cautious about interpreting what this fact means. The rise in diagnosis could reflect an actual increase in the rates of occurrence of these conditions, or it could be due to systemic overdiagnosis of these conditions by therapists and patients who find these conditions compelling and who are consequently motivated to see them occurring even when the underlying actual phenomena being observed might be more accurately characterized by alternative diagnoses such as borderline personality disorder or schizoaffective disorder.
Conventional clinical wisdom suggests that a precondition of the more severe dissociative disorders like DID is significant childhood trauma. A causal relationship is implicit in this “wisdom” to the effect that early trauma is thought to cause later dissociation in susceptible people. Dr. Kihlstrom has specifically examined whether evidence in support of this causal assumption could be generated in the lab. Importantly, he has concluded based on years of doing such research that trauma is not a precondition for developing dissociation disorders.
The idea that trauma causes dissociation disorders probably came out of early retrospective (backwards looking) research studies and case histories where someone with a dissociation disorder was asked about past events in their lives. Frequently, dissociative patients would self-report that they were abused or traumatized in some fashion. Problems with this retrospective methodology are numerous, however. Because there is a cultural idea that trauma causes dissociation, patients may have been motivated to see themselves as having been traumatized. Much of this retrospective research used very loose criteria in defining trauma, so much so that many non-traumatic events qualified as trauma when they shouldn’t have. Also, little of the reported past trauma was documented.
Dr. Kihlstrom talks about using a prospective research method (instead of a retrospective method) in order to try to compensate for the difficulties associated with this problematic retrospective self-recall methodology. Using prospective methodology, Dr. Kihlstrom started with traumatized patients who were not previously dissociative and followed them over time to see if some of these patients went on to develop amnesia for their traumas. When this did not happen he interpreted this to suggest that trauma probably was not causing dissociative symptoms like amnesia to occur. Similar lines of reasoning and experiment also supported this interpretation. Dr. Kihlstrom notes that the typical clinically significant response to trauma, namely Post-traumatic Stress Disorder (PTSD), involves the inability to forget trauma and not amnesia. He also notes that cases where amnesia does occur in the aftermath of trauma can typically be explained by taking into account the full inventory of complicating factors present during the trauma. For instance, in the case of amnesia in the aftermath of rape, such amnesia might be accounted for as an side-effect of victims’ intoxication, or as a complication of head injury sustained during the rape. Trauma or abuse may be present in the past histories of patients with dissociative disorders, but, in Kihlstrom’s view, such trauma history is more likely incidental than causal so far as dissociation is concerned. The true cause of dissociative disorders remains unknown, in his view.
Dr. Van Nuys and Dr. Kihlstrom talk about the controversial concept of recovery of repressed sexual abuse memories. Not surprisingly, Dr. Kihlstrom holds that such recovered memories are untrustworthy, and particularly so when hypnotic methods are used to bring them into a patient’s awareness. He notes that 1) hypnotic methods inherently involving suggestion, and that 2) there is a widely accepted and emotionally compelling myth that everyone receives from the culture that trauma causes dissociation. In the context of these two observations, it is all too easy for a hypnotherapist to suggest an interpretation of the past that did not actually occur, and/or for a patient to produce a “memory” of a past event that is based more on a compelling cultural myth than on actual events. It is impossible to know whether a recovered memory is an accurate representation of an event or if instead the memory is really a fantasy that feels true like a memory because it makes sense emotionally and mythologically/culturally.
To make the point about the unreliability of hypnotically recovered memories he describes the results of a study his mentor did years ago. College students were hypnotized and given the suggestion that they age-regress. While under the influence of the trance state, these students acted like children and drew pictures which the researchers saved and later compared to pictures each student had drawn when they were actually children which they got from the student’s parents’ attics. There were no substantive similarities between the actual- and age-regressed images suggesting that the college students were not actually accessing childhood memories and behavior patterns so much as they were imagining what it was like to be children from an adult perspective. In other words, you can get a very convincing portrayal of a child when you hypnotize someone and ask them to go back in time, but this portrayal is the adult’s imagination and interpretation being realized and not an actual recovery of older memory material.
According to Dr. Kihlstrom, there is research support for the concept of post-hypnotic amnesia (e.g., where a suggestion has been made during a trance that the subject forget something). What is particularly interesting about post-hypnotic amnesia, however, is that it affects the explicit memory system, but not the implicit memory system. Neuroscientists have identified two distinct types of human memory which they have labeled implicit and explicit. Explicit memory is conscious, episodic memory for events; the normal kind of memory people think of when they think of memory. Implicit memory is unconscious and is involved in learning to do procedures (like tie a shoe or play the piano). A hypnotic suggestion to forget an event might cause a person to forget that event, but it won’t cause that person to forget new procedures learned during that event. This same pattern of explicit memory amnesia but continuing-to-function implicit memory is also frequently observed in brain damaged patients with organic amnesia (such as the famous and recently deceased patient HM who experienced anteriograde (forwards in time) amnesia (e.g., an inability to form new memories) after surgery to address severe epilepsy. HM could not consciously remember anything new post-surgery, but he could learn new procedures just the same.
As the interview winds down, Dr. Kihlstrom spends some time differentiating the four different dissociative disorders.
The mildest and most common form of dissociative disorder is known as depersonalization disorder. This is something that happens to people during times of great stress where they experience a weird sensation that they have somehow changed and have become alien to themselves. A companion disorder involves “derealization” or the sense that the world has somehow weirdly changed and become alien. When depersonalization is transient it is not thought of as a disorder but rather a stress response. It is only when depersonalization becomes chronic that it becomes diagnosable.
Dissociative amnesia involves the forgetting of a circumscribed portion of memory. A person forgets the events that occurred during a big chunk of time, but not who they are (e.g., their identity).
Dissociative Fugue is a more severe form of dissociative amnesia in which the amnesia involves the loss of identity as well as memory for events. In cases of fugue a person may (or may not) take on a new identity. A key feature of fugue is that the person often goes traveling and is ultimately found living in a different city.
Dissociative Identity Disorder is the most severe form of dissociative disorder, involving the person alternating between various different identities each of which has its own set of circumscribed autobiographical memories.
Dr. Van Nuys closes the interview with a commentary, shared by myself (Dr. Dombeck), to the effect that he (we) will have to revise our understanding of the relationship between trauma and dissociative disorder in light of Dr. Kihlstrom’s comments here. We both had the understanding that substantive dissociative disorders like DID generally involve (and have been caused by) significant trauma, and we both will need to be disabusing ourselves of this notion in light of what we have learned. You live and you learn.