What is the difference between BPD and the spectrum of dissociative disorders?
In normal consciousness, we experience an exquisite and seamless integration of a variety of neurological functions. We are perceiving input via all five of our senses and integrating these perceptions into a meaningful picture of reality. Current experience is also influenced by memory traces from the past that are automatically called into awareness according to their relevance to the present. New memory traces are constantly being created and stored. And we must remember that we are not merely passive recorders of our environment but interact with it via our various motor functions, altering both our surroundings and our perceptions of them. Finally, to distinguish us from the computer on which I record this message, we experience emotions, which further color and individualize the content of consciousness.
Dissociation describes any conditions in which one or more of these functions fail to integrate and are split off or dissociated from the mainstream of experience. The dissociated piece may be a small fragment of a function, for example a specific memory of a single event in time, or it may be of more sweeping consequence, such as amnesia for the essential elements of one's identity.
Dissociation may affect memory creation or retrieval, any aspect of sensory input and interpretation, the capacity to execute motor functions such as movement or speech, and the emotional coloring of experience. The cognitive and emotional aspects of experience can be separated in more than one way. The perception of one's surroundings may be robbed of all emotional tone as in depersonalization. On the other hand, emotion can so dominate consciousness that it blots out current reality as might occur in the flashbacks that occur in Post-traumatic Stress Disorder.
Most of the dissociative disorders that have been defined are well-circumscribed in scope and may, in turn, originate with a single intense or traumatic emotional experience. There may be amnesia covering a specific event or period of time. There may be a discrete alteration of sensory input, such as tunnel vision or even an episode of psychogenic blindness (often interpreted as an unconscious unwillingness to view something painful). Motor functions may be affected as in the paralysis of a limb or an inability to speak (which may be understood as unconscious recognition that something is unspeakable). Such alterations of sensory or motor functions that are not based upon physical diseases characterize the conversion disorders along with pseudo seizures and other non-organic neurological dysfunctions. There may even be apparent alterations of the individual's usual cognitive abilities.
Any of the dissociative symptoms may occur in BPD. Dissociative experiences are a hallmark of BPD. They are generally more varied, more complex, and often more persistent than the single symptoms that characterize many dissociative disorders. All people with BPD dissociate. Only some people who dissociate have BPD.
At the other end of the complexity spectrum is Dissociative Identity Disorder. In Chapter 4 of Lost in the Mirror, I compared multiple personalities to the channels of a radio or television. With this model, the tuner would be governed by current circumstances and emotions, determining which personality would be tuned in at any given time.
A more timely analogy would be Windows. As our computers become increasingly sophisticated, I believe they approximate more and more closely how the brain actually works. We are capable, like our computers of processing more than one thing at a time. Our stored memories are like the hard disk. Our moment to moment mental processes resemble what a computer is processing in RAM. Consciousness is like the top window, with other functions running in the background. As I type this paragraph, my computer is using another part of its RAM to try to log onto AOL. While I select my words I am also aware of my aching muscles from an earlier workout and of rising tension as the hour advances and time begins to run out on this task. With all that and more going on in the periphery of consciousness, my brain is also regulating my heart rate, blood pressure, rate of respiration and other bodily functions.
In Dissociative Identity Disorder, the personalities are taking turns occupying consciousness, but they are all simultaneously present and processing experience. And while only one window is on top, sometimes fragments of the other windows can be seen around the edges. For example, hear ing voices could be understood as an intrusion of information from one window (or personality) into the space of another. Many forces determine which personality commandeers consciousness for the moment. If I drift from my task of writing, my screen saver will suddenly obscure this text. And even if I am intently persistent in my task, AOL will preempt the screen if it ever actually connects. Similarly, an alternate personality might take over when the attention of the personality occupying consciousness begins to drift or when an alter develops an urgent agenda that demands conscious attention.
Discontinuity of experience is perhaps the single most defining feature of BPD. DID is an extreme version of this fragmentation. I believe that every person with DID also meets criteria for BPD. Only a fraction of people with BPD, however, experience the degree of fragmentation that occurs in DID. The spectrum of dissociative disorders therefore begins at one end with single dissociative events, moves toward BPD in which the tendency to fragment experience is fundamental, and finally to DID, which may be understood as an extreme form of BPD in which the dissociative experiences are complex and systematized.
© Dr. Richard Moskovitz
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