Dennis Rader - the BTK Killer
Court Transcript of BTK's Confession. . .The Court: -- you were engaged in some kind of fantasy during this period of time?The Defendant: Yes, sir.The Court: All right. Now, where you use the term “fantasy,” is this something you were doing for your personal pleasure? The Defendant: Sexual fantasy, sir.
The Archives of General Psychiatry has published a neuroimaging study of nonconsensual sexual sadism in a forensic setting (Harenski et al., 2012), sure to be controversial among BDSM practitioners, DSM-5 critics, and Christian fundamentalists alike.
Here's a brief background and rationale for the study:
Context Sexual sadism is a psychiatric disorder in which sexual pleasure is derived from inflicting pain, suffering, or humiliation on others. While the psychological and forensic aspects of sexual sadism have been well characterized, little is known about the neurocognitive circuitry associated with the disorder. Sexual sadists show increased peripheral sexual arousal when observing other individuals in pain. The neural mechanisms underlying this unusual response are not well understood. We predicted that sadists relative to nonsadists would show increased responses in brain regions associated with sexual arousal (amygdala, hypothalamus, and ventral striatum) and affective pain processing (anterior cingulate and anterior insula) during pain observation.The participants were 15 violent sexual offenders housed at Sand Ridge Secure Treatment Center: 8 sadists and 7 nonsadists, as rated on the Severe Sexual Sadism Scale.1 One additional participant with an ambiguous score was excluded. The groups were fairly well-matched for age (about 50 yrs), education (12 yrs), IQ (92-97), substance use, and level of psychopathy.
The subtitle of the paper is Preliminary Findings and one must keep this in mind, given the small n in the groups.
The experimental design involved presenting a set of three images depicting (a) one person inflicting pain upon another ("Pain"), and (b) control images with two people but no pain inflicted ("No Pain"). The participants rated the severity of pain inflicted for each stimulus set on a 0-4 scale. A third condition depicted one person causing damage to an object, but those results were not presented in the paper.
Figure 1 (Harenski et al., 2012). Example of pain and no-pain picture sets, along with the pain severity rating scale.
By definition, sexual sadists obtain pleasure and gratification via the suffering of others. Here are the DSM-IV-TR diagnostic criteria (APA, 2000) for Sexual Sadism (see Krueger, 2010; PDF):
A. Over a period of at least 6 months, recurrent, intense sexually arousing fantasies, sexual urges, or behaviors involving acts (real, not simulated) in which the psychological or physical suffering (including humiliation) of the victim is sexually exciting to the person.B. The person has acted on these sexual urges with a nonconsenting person, or the sexual urges or fantasies cause marked distress or interpersonal difficulty.2
So it comes as no surprise that brain regions associated with sexual arousal were predicted to show greater activity to Pain in the sadists. What are the "sexual arousal areas"? According to the authors, these include the amygdala, hypothalamus, and ventral striatum. The problem is that none of these areas is selectively involved in sexual arousal [with the possible exception of specific hypothalamic nuclei]. In fact, the amygdala is more often related to fear, so greater activity might also be expected in those who take the perspective of the victim.
The other major prediction was that activity in the "affective pain areas" (anterior cingulate cortex and anterior insula)3 would be greater to Pain images in the sadists, because they are actually more sensitive to the suffering of others. This might seem counterintuitive in such callous individuals, but...
In any scenario where pain is imminent, sadists may pay closer attention than nonsadists to the thoughts and feelings of the victim because this enhances their sexual arousal when pain is inflicted. In other words, whereas sadists lack sympathy for their victims, they may exhibit empathy (simulating their victims' feelings) when consistent with their goals.In support of this view, the sadists rated Pain pictures as higher in severity than the nonsadists did. The two groups did not differ in their ratings of No-Pain pictures. In the future, comparison to a control population of nonviolent offenders would be helpful.
Since Sand Ridge does not have its own scanning facility [gasp!], running the fMRI experiment involved use of a mobile unit.
Kent Kiehl outside the mobile scanner he has used to look at the brains of inmates at a New Mexico prison. Credit: Nature News.What were the results of the imaging study? The sadists showed greater activity to Pain (vs. No-Pain) in the left amygdala, but the nonsadists did not. The right ventral striatum showed a main effect of group (greater activation in the sadists) which did not differentiate between Pain and No-Pain pictures. No significant effects were observed in the hypothalamus.
Figure 3 (Harenski et al., 2012). A, Interaction in the left amygdala, representing increased response during pain vs no-pain picture viewing in sadists but not in nonsadists. B, The mean parameter estimates are for the cluster at Montreal Neurological Institute coordinates x = –21, y = –6, z = –21. Bars indicate standard errors.
Overall, it's not clear whether the amygdala result is related to sexual arousal at all. The participants were not asked if they found the pictures arousing (nor were any peripheral signs of this measured).
Finally, activity in a region of the left anterior insula showed a positive correlation with pain severity ratings in the sadists but not in the nonsadists. This could mean they were more attuned to the suffering of others, but it could also mean they experienced a higher level of disgust (unlikely, but see Jabbi et al., 2008).
The authors end on a speculative (and controversial) note, wondering whether the "neural abnormalities" of incarcerated sadistic sexual predators would generalize to those who engage in consensual sadism:
It is interesting to consider whether the neural abnormalities that characterize incarcerated sexual sadists generalize to individuals in the community with sadistic sexual preferences. Sadists who offend may differ from those who do not in early environment (eg, abuse or inadequate social and family environment). Individuals involved in consenting sadomasochistic relationships are also different from criminal sadists because criminal sadists do not generally engage in sadomasochism, nor do those in sadomasochistic relationships generally victimize others. Nonetheless, all experience sexual arousal to pain infliction. Therefore, whether the present results generalize to all sadists is a question for future research.
Footnotes
1 This scale is:
an 11-item scale rated according to history of sexual behavior. Items are rated yes (1 point) or no (0 points) and include the following: (1) engages in gratuitous violence toward or wounding of victim; (2) exercises power, control, or domination over victim; (3) humiliates or degrades victim; (4) is sexually aroused by the act; (5) tortures victim or engages in acts of cruelty to victim; (6) shows evidence of ritualism in offense; (7) abducts or confines victim; (8) inserts object or objects into victim's bodily orifice or orifices; (9) mutilates sexual parts of victim's body; (10) mutilates nonsexual parts of victim's body; and (11) keeps trophies (eg, underwear or identification) of victim or keeps records of the offense. To meet sexual sadist criteria, an offender's behavior must include at least 4 items (3 of which must be items 2-5 or item 9).It is considered more reliable than DSM-IV and PPG-based (penile plethysmography) diagnoses.
2 Krueger noted [PDF]:
The change in the B. criterion from DSM-IV to DSM-IV-TR represents one of the few changes in criteria from DSM-IV to DSM-IV-TR. This change was made to all of the paraphilias which involved a victim, to remove any ambiguity about whether acting out sexual urges with others was sufficient for a diagnosis; some had argued that an individual with a paraphilia who was not distressed about his or her behavior could not be diagnosed with a paraphilia, and this new wording allowed for a diagnosis to be made in such a circumstance.The addition of "nonconsensual" was also instituted in 2000, thereby depathologizing those who engage in consensual BDSM activities.
3 To avoid becoming too pedantic, I won't expound on how anterior cingulate and insular cortices are not specific to affective pain processing. These two regions are activated by most everything:
...(the insular cortex) is a brain region that is active in as many as one third of all brain imaging studies.
References
Harenski, C., Thornton, D., Harenski, K., Decety, J., & Kiehl, K. (2012). Increased Frontotemporal Activation During Pain Observation in Sexual Sadism: Preliminary Findings. Archives of General Psychiatry, 69 (3), 283-292. DOI: 10.1001/archgenpsychiatry.2011.1566
Jabbi M, Bastiaansen J, Keysers C. (2008). A common anterior insula representation of disgust observation, experience and imagination shows divergent functional connectivity pathways. PLoS One 3(8):e2939.
Krueger RB (2010). The DSM diagnostic criteria for Sexual Sadism. Arch Sex Behav. 39:325-45 [PDF].
Further Reading
"None of us are saints"
-serial child killer and cannibal, Albert Fish Humor, Hot Flashes, and Empathy for Pain Hah-Ha! I Feel Your Pain, I REALLY Do: Synaesthesia for Another's Pain Pleasure or Pain? Tales of Passion and Disgust The Disconnection of Psychopaths
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