Friday, November 20, 2009

Bleed It Out

I've opened up these scars
I'll make you face this
I pulled myself so far
I'll make you, face, this, now!
---Linkin Park

Deliberate self-harm, or self-injury, is becoming increasingly recognized as a problem affecting adolescents and young adults. Rates are difficult to determine, as the behaviors are often concealed. One recent study tracked a group of 1400 Midwestern US high school students over a 5 year period (Muehlenkamp et al., 2009). Rates of non-suicidal self-injury (NSSI) over 2001-205 were as follows:

Besides being associated with depression and eating disorders (especially among girls), the current psychiatric bible (DSM-IV-TR) includes self-injury as one of nine diagnostic criteria for Borderline Personality Disorder:
Recurrent suicidal behavior, gestures, threats or self-injuring behavior such as cutting, interfering with the healing of scars (excoriation) or picking at oneself.
Other criteria of BPD include:
  • A pattern of unstable and intense interpersonal relationships characterized by alternating between extremes of idealization and devaluation.
  • Identity disturbance: markedly and persistently unstable self-image or sense of self.
  • Impulsivity in at least two areas that are potentially self-damaging (e.g., promiscuous sex, eating disorders, binge eating, substance abuse, reckless driving).
  • Affective instability due to a marked reactivity of mood (e.g., intense episodic dysphoria, irritability or anxiety usually lasting a few hours and only rarely more than a few days).
Although it's considered a very serious personality disorder, the diagnostic label is a controversial one, coming under fire from feminists (Shaw & Proctor, 2005) and from some psychiatrists, like Dinah at Shrink Rap (see Over The Border Line).

Why Do Cutters Have Reduced Pain Perception?

An earlier study by Schmahl et al. (2006) examined the Neural correlates of antinociception in borderline personality disorder during the administration of heat pain. Do borderline patients injure themselves to "feel" (or "feel more normal") OR to down-regulate the emotional components of pain? The results didn't really answer this question, but the authors gave two options:
Limbic deactivation has been found to correlate with the degree of coping in aversive situations in general. . . . Thus, in view of these findings, self-inflicted pain may function to normalize neural activity in specific brain regions involved in emotional and cognitive processing. Alternatively, repeated self-injury could lead to an adaptation of pain thresholds and pain processing reflected in the current findings of elevated pain thresholds and disturbed prefrontal and limbic pain processing.
A new fMRI study by Kraus et al. (2009) took a different approach and compared BPD patients and controls who listened to standardized scripts of self-injurious behavior while in the scanner. The procedure was as follows:

Script-driven imagery was utilized to deliberately evoke emotional distress. The segments were Neutral (a woman on a shopping trip), Trigger (the woman watching a dispute between a mother and her child), Cognitive and Emotional Reactions (think about similar situations with your own mother), Self-Injurious Behavior (a typical act is described, from preparation to cutting itself), and Relaxation (presumably including the SI-induced decrease in aversive inner tension in BPD).

For the between-group comparisons, the imaging data weren't particularly strong at revealing robust differences. The primary finding was reduced activity in left orbitofrontal cortex in the BPD patients during the Cognitive and Emotional Reaction phase, possibly reflecting dysregulation of emotional control. However, the most intriguing finding in my view was deactivation in mid-cingulate cortex during the Self-Injury script. Although the authors didn't plot this result, the coordinates for the deactivation overlap with regions of the anterior cingulate involved in the affective components of pain (Rainville et al., 1997).

What's plotted below is the result of a coordinate-based meta-analysis of the neuroimaging literature on pain perception using the activation likelihood estimation (ALE) method. Articles on physical pain were identified in the BrainMap database (see Hypnosis and Pain Control for details). Of relevance for our current purposes is this midsaggital slice showing strong activation across studies of pain perception in a region of the anterior cingulate cortex that showed deactivation in the BPD patients during the self-injury script (the precise focus is indicated by the blue crosshairs). Although very preliminary, this finding may suggest that imagining an act of self-injury may downregulate the affective component of pain in individuals with borderline personality disorder.

As always, there are limitations with such a pilot study. The authors even list them at the outset:
  • Fixed-effects analyses limit the ability to generalize from the study sample to the larger population of patients with borderline personality disorder (BPD).
  • Due to the study design, a single section of the script could not be repeatedly presented, thus possibly diminishing the effect size of our results.
  • As no control script was used, it cannot be determined whether our findings are related to self-injurious behavior (SIB) per se or to BPD features in general.
Nonetheless, Kraus et al. are continuing to expand on this work with fMRI studies that more closely mimic SIB than the present script design.


Kraus, A., Valerius, G., Seifritz, E., Ruf, M., Bremner, J., Bohus, M., & Schmahl, C. (2009). Script-driven imagery of self-injurious behavior in patients with borderline personality disorder: a pilot FMRI study. Acta Psychiatrica Scandinavica DOI: 10.1111/j.1600-0447.2009.01417.x

Muehlenkamp JJ, Williams KL, Gutierrez PM, Claes L. (2009). Rates of non-suicidal self-injury in high school students across five years. Arch Suicide Res. 13:317-29.

Rainville P, Duncan GH, Price DD, Carrier B, Bushnell MC. (1997). Pain affect encoded in human anterior cingulate but not somatosensory cortex. Science 277:968-71.

Schmahl C, Bohus M, Esposito F, Treede RD, Di Salle F, Greffrath W, Ludaescher P, Jochims A, Lieb K, Scheffler K, Hennig J, Seifritz E. (2006). Neural correlates of antinociception in borderline personality disorder. Arch Gen Psychiatry. 2006 Jun;63(6):659-66.

Shaw C, Proctor G. (2005). Women at the Margins: A Critique of the Diagnosis of Borderline Personality Disorder. Feminism and Psychology 15:483-490.

I bleed it out digging deeper
Just to throw it away
I bleed it out digging deeper
Just to throw it away
I bleed it out digging deeper
Just to throw it away

Just to throw it away
Just to throw it away
I bleed it out

Bleed It Out
---Linkin Park

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