Our work on pain offset relief showed us that such SITB benefits are not unique to people who engage in SITBs. Although these mechanisms help us understand how SITBs work, they're not risk factors because they don't divide people into high and low risk groups. As a result, these benefits don't help us to identify people who may be at-risk and they aren't great treatment targets. All of this led us to another question that has inspired much of our recent research:
If self-injury can make everyone feel better, what keeps most people from engaging in self-injury? Phrased another way: What must people overcome in order to engage in SITBs?
There are many potential answers to this question, but we started with two that seemed most obvious to us: (a) pain, and (b) aversion to SITB-related stimuli. These initial ideas were inspired in part by Joiner's (2005) concept of suicidal capability. We initially applied these ideas to nonsuicidal self-injury (NSSI), but more recently have expanded to suicidal self-injury and concepts beyond capability.
Do people who engage in NSSI feel pain (and if so, do they feel less)?
Answer: Yes, they do feel pain, but on average they tend to show higher pain thresholds and tolerances than most other people.
Most people reject the idea of self-injury immediately because when they imagine it, they imagine it as painful. We hypothesized that the physical pain involved in self-injury is a major barrier that people who engage in these behaviors overcome. One possibility was that people who engage in NSSI feel pain normally but just push themselves to tolerate it; another possibility was that people who engage in NSSI simply felt far less pain than other people. To investigate this, we conducted a couple of studies that used the cold pressor task (i.e., very cold water) to examine whether people with a history of NSSI show any differences on pain threshold (i.e., when someone first reports feeling pain) and pain tolerance (i.e., how long someone will tolerate pain).
The basic results are presented below:
Results fell somewhere in between the two possibilities that we noted above. People who engage in NSSI take a little longer to report that they're feeling pain (threshold) and will tolerate pain for much longer than most people (tolerance). These findings showed that people who engage in NSSI process pain abnormally, but could not address why this occurred.
Recommended citations for this information: Franklin, J.C., Hessel, E.T., & Prinstein, M.J. (2011). Clarifying the role of pain tolerance in suicidal capability. Psychiatry Research, 189, 362-367.
Franklin, J.C., Aaron, R.V., Arthur, M.S., Shorkey, S.P., & Prinstein, M.J. (2012). Nonsuicidal self-injury and diminished pain perception: The role of emotion dysregulation. Comprehensive Psychiatry, 53, 691-700.
Why is nssi associated with abnormal pain perception?
Answer: The best-supported answer at this time is that people who engage in NSSI believe that they deserve the pain involved in these behaviors.
Many researchers assumed that abnormal pain perception among people who engage in NSSI was due to some kind of neurological condition. Although this was possible, we believed that psychological mechanisms may play a large role. We tested these by investigating whether affect dysregulation mediated the association between NSSI and pain tolerance (while controlling for other potential mediators).
The basic results were as follows:
Results showed that, even in the context of other mediators, affect dysregulation mediated the association between NSSI and pain tolerance. Moreover, affect dysregulation was associated with higher pain tolerance in both the NSSI group and the control group -- suggesting that this is a more general mechanism rather than an NSSI-specific mechanism. One major limitation of these findings is that affect dysregulation is a vague construct, so it is of limited value in helping us to explain exactly why/how the NSSI-pain association exists. Fortunately, great work by our collaborator, Dr. Jill M. Hooley, has specified that a small facet of cognitive-affect dysregulation called self-criticism appears to go a long way toward explaining this association. Her work indicates that some people believe that they deserve pain and punishment and this motivates them to self-injure (vs. other behaviors) and to endure intense pain for longer than most other people.
Recommended citation for this information: Franklin, J.C., Aaron, R.V., Arthur, M.S., Shorkey, S.P., & Prinstein, M.J. (2012). Nonsuicidal self-injury and diminished pain perception: The role of emotion dysregulation. Comprehensive Psychiatry, 53, 691-700.
Also see Dr. Hooley's work here
Do people who engage in nssi find injury/mutilation Stimuli to be pleasant?
Answer: On average they find them to be slightly unpleasant or neutral, but recent/frequent self-injury is associated with finding such stimuli to be pleasant.
Most people find pictures of blood, knives, and wounds to be even more unpleasant than stimuli like spiders, snakes, and disease. We hypothesized that this acts as another barrier that prevents most people from engaging in NSSI. Whereas most people are disgusted at the thought of wounds/knives, some people may actually be attracted to these stimuli. We tested this possibility by examining explicit (i.e., self-report), implicit (i.e., Affect Misattribution Procedure), and physiological (startle eyeblink) reactions to pleasant, neutral, unpleasant, and NSSI-related images. Results were the same across all measures, but for brevity we'll only present the explicit results here:
We found that ratings between groups were very similar across pleasant, neutral, and unpleasant categories, suggesting that people with a history of NSSI tended to process/rate emotional stimuli normally. But, consistent with our expectations, they rated NSSI-related pictures as significantly more positive, suggesting that they generally did not mind these stimuli. Results also revealed that the more recently and frequently some had engaged in NSSI, the more they tended to like these stimuli -- with many participants rating these images as extremely pleasant. This suggested to us that this 'diminished aversion to NSSI stimuli' may be the result of conditioning processes and may be a risk factor for future NSSI.
Recommended citation for this information: Franklin, J.C., Lee, K.M., Puzia, M.E., & Prinstein, M.J. (2014). Recent and frequent nonsuicidal self-injury is associated with diminished implicit and explicit aversion toward self-cutting stimuli. Clinical Psychological Science, 2, 306-318.
Does Diminished Aversion to NSSI Stimuli Predict Future NSSI?
Answer: Yes, even after controlling for several competing predictors.
As our meta-analytic work has shown, many powerful correlates of self-injury do not actually predict future self-injury very well. In other words, they are poor risk factors. To test whether diminished aversion to NSSI stimuli is a risk factor for future NSSI, we measured diminished aversion and followed participants for six months. Across all three measurement types, diminished aversion was strongly correlated with future NSSI, even after controlling for several competing predictors. This provided preliminary evidence that diminished aversion is a risk factor for future NSSI. However, this study was small and most participants were not high frequency self-injurers, so much more work is needed.
Recommended citation for this information: Franklin, J.C., Puzia, M.E., Lee, K.M., & Prinstein, M.J. (2014). Low implicit and explicit aversion toward self-cutting stimuli longitudinally predict nonsuicidal self-injury. Journal of Abnormal Psychology, 123, 463-469.
This work has been a very fruitful initial foray into the topic of SITB barriers, but it's only the start. We have just completed several large follow-up studies that included more severe participants and focused more directly on suicidal self-injury. We plan to continue this work and to investigate additional barriers to SITBs.