Emotions and pain in deliberate self-harm

by Michael D. Anestis, M.S.

The first couple weeks of internship have been a pretty serious adjustment, but so far it’s been a phenomenal experience.  The research opportunities I’ve encountered between here and back in Tallahassee have been remarkable, with a silly number of projects bouncing through my head at once.  This means good things for my professional productivity, but less good things for my ability to write frequently for PBB.  That being said, a couple days ago, I received a copy of an in press article directly relevant to the work I have done and am doing on emotion dysregulation and pain tolerance and it was too cool (in the nerdy sense of the word “cool”) not to write about here.  Now, in the interest of full disclosure, I am currently working with Kim Gratz and Matt Tull here at the University of Mississippi Medical Center, so I’m not coming at this from an unbiased angle.  That being said, I want to discuss the data from this particular study, so any bias I may have regarding the importance of the findings should have little bearing on what you actually conclude on your own.

The paper itself, which is in press at Comprehensive Psychiatry, was co-authored by Kim Gratz, Claire Hepworth, Matt Tull, Autumn Paulson, Sue Clarke, Bob Remington, and Carl Lejuez and it takes a look at emotional distress and pain tolerance in individuals with and without a history of deliberate self-harm (DSH).  You might remember from my earlier discussions of the interpersonal-psychological theory of suicidal behavior that current research on suicide points towards a lifetime accumulation of painful and provocative experiences as a key component of suicide risk, as such experiences appear to increase an individual’s ability to tolerate physical pain and decrease an individual’s fear of death, thereby making them capable of engaging in the inherently terrifying and painful experience of a suicide attempt with a high likelihood of lethality.  The authors of this study, however, noted that past research has indicated that patients diagnosed with borderline personality disorder (BPD) only exhibited a higher level of pain tolerance than healthy controls and individuals with other personality disorders under conditions of increased stress (McCown, Galina, Johnson, DeSimone, & Posa, 1993).  If that is the case – that particular individuals’ ability to tolerate pain increases only when they are distressed – this is an extremely important point to consider.  This could mean that, faced with intense emotional pain, such individuals are willing to accept physical pain as long as it offered at least temporary relief from their emotions.  If you think back to our discussions of the functional model of non-suicidal self-injury (NSSI), this makes sense and makes the idea of self-injury in an effort to feel better make a bit more sense.  At the same time, if you think back to our discussion about impulsivity and suicide, there’s a bit of a conflict here in that suicide attempts are not typically impulsive (e.g., Witte et al., 2008) and the more impulsive an attempt is, the less medically serious it tends to be (e.g., Baca-Garcia et al., 2001).

My interest in this topic was piqued because I am currently looking at the impact of emotion dysregulation on various indicators of suicide risk and, given that pain tolerance is theorized to be a fairly stable risk factor, the main hypothesis of this paper has significant implications.  In this particular study, Gratz and her colleagues (in press) recruited 43 individuals with a history of DSH and 52 participants with no such history.  Participants filled out a number of questionnaires detailing self-harm tendencies, BPD symptoms, and depression symptoms.  Participants were then asked to think of two recent interpersonal situations, one of which involved an interaction that left them “very angry and upset” and one of which left them feeling “mostly neutral.”  Their descriptions of the situations took approximately 30 minutes and were recorded and then turned into a 1-minute summary recorded by a member of the research team.  Participants were then randomized to either receive their neutral script or their upsetting one.  As a measure of emotional willingness, participants also took part in a computerized mirror-tracing persistence task.  Participants were told to use the mouse to trace a thin line on the screen, but the mouse was programmed to move the cursor in the opposite direction from which it was moved by the participant, rendering the task nearly impossible.  This task has been shown in the past to induce distress in laboratory participants and willingness was calculated by examining how long the participant was willing to continue trying before quitting.  Two measures of pain tolerance were then administered to each participant.  The first, a cold presser, involves participants putting one arm in an extremely cold container of water (33 degrees) and keeping it there as long as they could tolerate the discomfort.  The second, a pressure algometer (which I used in my most recent study) involves using a device that squeezes participants’ pointer finger on the bone of the top joint until they can no longer tolerate the discomfort.  At four points throughout the study, participants filled out a measure indicating their current levels of positive and negative emotions: at baseline, following the interpersonal script, following the mirror-tracing task, and following the pain tolerance task.

So…what did they find?  First of all, females with a history of DSH were more willing to tolerate emotional distress (they persisted longer in the mirror tracing task) than controls did when they were in the condition that involved listening to a 1-minute script of their neutral interaction.  Females with DSH were less willing to tolerate emotional distress than controls, however, when they were in the distressing condition.  Men, on the other hand, exhibited the opposite pattern, which was not an expected result.  The authors had a number of thoughts as to why this pattern emerged.  First, it might be that emotional willingness is more relevant to DSH in women than in men.  Alternatively, it might be that men, after hearing their distressing interaction script, viewed the mirror tracing task differently than did women, perhaps viewing it as an opportunity to excel, and therefore were less motivated to escape from the task.

With respect to pain tolerance, results indicated that individuals with a history of DSH who were in the distressing condition exhibited the highest level of pain tolerance.  This, as I mentioned earlier, is very important.  It means that certain individuals become willing to tolerate physical discomfort when they are upset, perhaps because the aversive physical sensations distract them from aversive affective sensations, which they view as less tolerable.  To me, the biggest issue here is the point that pain tolerance is not necessarily consistent within an individual regardless of the context.  Depending on how they are feeling emotionally, they might be willing to tolerate more (or less) physical pain.  That being said, I think another more cautious way to view this would be to make a parallel to weight.  We do not weigh one specific number of pounds – our weight fluctuates throughout the day – meaning that what we really have is a natural weight range.  I suspect pain tolerance is the same – that as an individual experiences more pain and provocation, both the bottom and top of that range increase, but that where the individual is within that range will vary depending upon their current level of emotional distress.
I am currently working on a couple of papers looking at self-reported and behaviorally measured distress tolerance with respect to pain tolerance and my results are looking a bit different than this, but my sample is also very different.  It will be interesting to see the degree to which these results are consistent across populations, as this will provide us with incredibly valuable information regarding how and in what ways particular individuals become vulnerable to both non-suicidal self-injury and suicidal behavior.

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Mike Anestis is a resident at the University of Mississippi Medical Center