Earlier this morning, I went to the dentist to get my teeth cleaned. Ordinarily, this is a fairly aversive experience, but this morning I barely noticed what was happening. As the technician scraped at my teeth, my mind was elsewhere – planning the rest of my day, replaying incidents from previous days – and I was not truly even aware of what she was doing. During this stretch of time, I was not attending to the stimuli in my immediate environment. Much as we often do not notice what other people in the room are doing when we are involved in a conversation or watching a television show, I simply was unaware of what was happening in front of me – but in this case, my attention was focused on my own thoughts rather than another aspect of my physical environment. My experience at the dentist was a mild form of what is known as dissociation. Dissociation involves both physical and cognitive symptoms, including but not limited to a sense of being removed from one’s environment or body, a sense that things are not real, and physical and/or emotional numbness.
Everyone dissociates and, far more often than not, doing so is not pathological. We dissociate when our mind wanders during a conversation or lecture and we suddenly realize we do not know what the other person was talking about. We dissociate when we are driving and suddenly realize that we can not recall the previous ten minutes and are unsure how we could have possibly obeyed the laws of the road. For some individuals, however, dissociation is a chronic, problematic experience. Several DSM-IV-TR disorders are characterized by dissociation, including dissociative disorders and post-traumatic stress disorder. In this article, however, I would like to focus on another disorder frequently characterized by the experience of dissociation: borderline personality disorder (BPD).
The DSM-IV-TR criteria for BPD includes transient dissociative experiences in response to stress. The precise definition of dissociation in the DSM is: “a disruption in the usually integrated function of consciousness, memory, identity, or perception of the environment.” (p.519) This is an extremely broad definition, which might explain the ambiguous nature of some of the research on this topic. After all, if researchers and clinicians can not fully agree on what it means to dissociate, they are likely to struggle in their efforts to uniformly measure and study the phenomenon.
Although there is substantial disagreement on certain aspects of dissociation, it still seems worthwhile to briefly summarize what we have discovered about the phenomenon in individuals diagnosed with BPD. One common finding, and the source of much of the controversy on this matter, is that dissociation is correlated with childhood mistreatment. Numerous studies have presented evidence in support of this idea. For instance, Watson, Chilton, Fairchild, and Whewell (2006) found that individuals diagnosed with BPD who dissociate regularly report greater levels of childhood emotional and physical abuse as well as emotional neglect. Childhood sexual abuse, however, did not predict levels of dissociation in individuals with BPD. Van Den Bosch, Verheul, Langeland, and Van Den Brink (2003), found that dissociation scores for women with BPD were higher amongst those who reported both sexual and physical abuse prior to age 16, more than one perpetrator, and severe maternal dysfunction. Brodsky, Cloitre, and Dulit (1995) found that women with BPD who dissociate are more likely to report a history of childhood abuse than are women with BPD who do not dissociate.
Clearly, these findings indicate that a positive correlation exists between self-reported childhood mistreatment and dissociation in women with BPD, but there are some weaknesses to the methods used and some contradictory findings that require consideration. First, even in the findings reported above, there is an element of disagreement in that childhood sexual abuse sometimes does and sometimes does not correlate with dissociation. Second, as pointed out by Giesbrecht, Lynn, Lilienfeld, and Merckelbach (2008), the studies that report the link between trauma and dissociation tend to utilize samples with high levels of pathology and rely on retrospective self-report. As such, the findings may not generalize to the rest of the population. Plus, individuals with high levels of dissociative symptoms tend to endorse symptoms and experiences on self-report scales that are intended to identify malingerers (e.g., Giesbrecht & Merckelbach, 2006). This is not to say that individuals who dissociate are lying when they report childhood trauma, but rather that retrospective self-report measures tend to result in unreliable findings whether due to misunderstanding of questions, confusion regarding memories and imagined scenarios, or a variety of other potentially confounding variables. Additionally, the effect sizes reported in studies that link childhood trauma to dissociation have, historically, been quite small. In fact, in two studies in which a researcher blind to the dissociation levels of participants examined hospital records of childhood trauma, no significant link between childhood trauma and dissociation was found (Cima et al., 2001; Sanders & Giolas, 1991). In a study on male patients and prisoners with BPD, Timmerman and Emmelkamp (2001) found that, while there was an association between sexual abuse and BPD, no such relationship existed between sexual abuse and dissociative symptoms. Quite clearly, there is substantial disagreement regarding the impact of childhood trauma on the development of dissociative tendencies. The common perception that childhood trauma is the primary cause of dissociative symptoms, however, does not have sufficient empirical support to be conclusively adopted and, in fact, seems to be contradicted by some compelling data.
There is similar confusion regarding the genetic heritability of dissociative tendencies. Lang, Paris, Zweig-Frank, and Livesley (1998) found that half of the variance in dissociative experiences could be accounted for by heritability. Waller and Ross (1997), however, found no evidence for a genetic basis for dissociation. As such, both environmental and genetic models for the development of dissociation have resulted in mixed findings. This could mean a variety of things, but a likely explanation is that the definition and measurement of dissociation is too broad and, as such, it is difficult for researchers to report consistent findings, as each research team is likely emphasizing different components of dissociation.
DaydreamingSo what do we know for certain about dissociation in individuals with BPD? Quite a few things, actually. For one thing, there is compelling evidence that individuals with BPD dissociate more often in proportion to the amount of tension they experience. In a study in which “aversive tension” was defined as a vague state of unidentified negative emotions, Stiglmayr, Shapiro, Stieglitz, Limberger, and Bohus (2001) found that the duration and intensity of aversive tension was positively correlated with the experience of both somatic and cognitive dissociative symptoms. This indicates that, consistent with the DSM-IV-TR criteria, individuals with BPD dissociate in response to intense experiences of negative affect. Dissociation in this case likely reflects not only an inability to differentiate between emotional experiences (e.g., anger versus frustration or sadness), but also a lack of emotion regulation skills. This is an important point to consider in light of the proneness of individuals with BPD to engage in non-suicidal self-injury (NSSI). Remember from our discussion of Nock and Prinstein’s (2004) functional model of NSSI that individuals self-injure for a variety of reasons, one of which is to “fee something, even if it is pain (intrapersonal positive reinforcement).” Dissociation often involves a sense of being distant or removed from one’s environment and a sense of emotional and/or physical numbness. A prolonged numb state can be an aversive experience that, for some, may serve as a precipitating factor for NSSI. In fact, Brodsky and colleagues (1995) reported that individuals with BPD who dissociate are more likely than individuals with BPD who do not dissociate to report engaging in NSSI.
Building off of the NSSI implications, Ludascher and colleagues (2007) found that, in individuals with BPD, high levels of dissociation are correlated with higher pain thresholds. In other words, the more an individual with BPD dissociates, the longer it takes for them to detect physical pain. This has important implications for suicide risk. In a prior discussion on Joiner’s (2005) interpersonal-psychological theory of suicidal behaviour, we discussed the acquired capability for suicide – a gradual habituation to physiological pain and the fear of death through repeated exposure to painful and provocative events. If individuals with BPD who dissociate are more likely to self-injure and less able to detect physiological pain, they will likely also report higher levels of the acquired capability for suicide, thus dramatically increasing suicide risk. Importantly, the findings reported here involve pain threshold, the point at which an individual detects pain, and not pain tolerance, the point at which the individual can no longer stand the pain. As such, future research is needed that directly measures pain tolerance.
Additionally, Jones and colleagues (1999) reported that, in individuals diagnosed with BPD, dissociation predicted the number of general memories recalled. In other words, the more often an individual with BPD dissociates, the more likely it is that he or she will experience difficulties recalling specific autobiographical experiences. Similarly, several studies have found that dissociation correlates highly with a tendency to experience everyday cognitive failures such as forgetting names, being distracted from tasks, and missing road signs (Merckelbach, Muris, & Rasin, 1999). These findings are one of the primary reasons that retrospective self-report measures are not an ideal assessment tool for examining childhood trauma in individuals who dissociate.
Ultimately, we appear to know more about the effects of dissociation in BPD (and in general) than its origins. Contradictory findings can be frustrating in this sense, but regardless, the focus remains the same: how do we treat it? We have discussed dialectical behaviour therapy (DBT; Linehan, 1993) at length in PBB and will continue to do so, but for the purposes of this particular article, it will suffice to say that this particular treatment, with its focus on mindfulness, appears to be an effective intervention technique. Importantly, readers should remember that dissociation in and of itself is not necessarily problematic. We all do it from time to time, particularly when we are tired, ill, or upset or – like me at the dentist’s office earlier today – starving. When such experiences become frequent and cause distress and impairment in our lives, dissociation should then be considered problematic and help should be sought.
This post is by Mike Anestis who is a doctoral candidate in the clinical psychology department at Florida State University