Are their brains not wired to feel what others feel, or do they just not care? Alison Abbott joins researchers looking into normal neurobiology through the scope of psychopathy.
It is a rare event that patient 13 is let out of the high security Dr S. van Mesdag Clinic in Groningen, the Netherlands, and he is making the most of the attention he is getting. Already, the prison guards have had to accompany him from the University of Groningen's functional magnetic resonance imaging (fMRI) scanner to the toilet four times in two hours. The guards indulge him with a shrug. Research psychologist Harma Meffert, who has recruited him for her study, is just as tolerant. That can't be easy, given that she has to spend at least 20 minutes resettling him into the scanner after each interruption
Wearing nothing but blue cotton surgical pyjamas and a constant smile, patient 13 doesn't seem to present much of a threat. In fact with his jewellery removed and his tattoos covered he looks decidedly small and vulnerable. But no one is forgetting why he was recruited to Meffert's study. Patient 13 has scored the maximum possible on the Psychopathy Checklist-Revised (PCL-R) rating scale, the ubiquitous tool psychiatrists use to identify the personality and behavioural traits that define the clinical syndrome 'psychopathy'. Lack of empathy is a key feature.
As it happens, Meffert's lab chief, Christian Keysers, the 34-year-old director of the university's neuroimaging centre, is not primarily interested in psychopathy per se. The major focus of his research is empathy ? the way we can't help feeling awful when we see a loved one cry, or can't stop our stomach sinking when someone's face darkens in anger. One major theory holds that we understand what another person is feeling by activating the same neural circuitry in our brains that activates when we are experiencing that emotion first hand.
To investigate this trait, Keysers is comparing 'normally' empathic people with those who lack empathy, such as people with autism, and psychopaths. He suspects that psychopaths may be able to recognize emotions in others but that they are also able to disconnect that recognition from their own emotions. ?Our question is: do they do terrible things to other people because, unlike most of us, they do not share the pain they inflict?? says Keysers. His sophisticated trial design is intended to test whether this is the case (see 'Letting fingers do the talking').
Although not all diagnosable psychopaths are criminally inclined or in prison, places such as the Groningen clinic serve as a concentrated source. And they provide screening. The PCL-R scale is practically the only tool available for this purpose. In PCL-R assessment, specially trained psychiatrists discuss hundreds of issues with the patient during semi-structured interviews. On the basis of these interviews, and information about past behaviour from independent sources, such as social workers' reports, they build up a four-part assessment. The headings are: 'interpersonal', covering behaviour such as manipulativeness and lying; 'affective', covering irresponsibility and lack of empathy and remorse; 'lifestyle', tracking impulsivity and need for stimulation; and 'antisocial', which looks for records of things such as juvenile delinquency. Those on the receiving end of the assessment find it tiresome.
Do they do terrible things to other people because, unlike most of us, they do not share the pain they inflict? Christian Keysers
It is, of course, not easy to put together a group of imprisoned psychopaths for an academic research project, but the Dutch Ministry of Justice provides generous access. ?We have a legal duty to try to treat all those criminals who are found guilty but not responsible for their actions due to insanity,? says Jacqueline Hochstenbach, a department head at the ministry.
Although the Groningen project doesn't aim to treat or cure psychopathy, there's a general sense even among the subjects that such basic research could at least help illuminate what is wrong. For psychopaths who are deemed dangerous, there are no therapeutic options. ?We know there is no effective treatment for psychopathy,? says Hochstenbach. Pharmaceuticals don't help and those who receive behavioural therapy have a higher ? not lower ? rate of recidivism.
In 2004, like other countries, the Netherlands institutionalized PCL-R testing in forensic psychiatric centres, where it is used as a risk-assessment tool for patients being considered for parole. Developed over the past three decades by psychologist Robert Hare from the University of British Colombia in Vancouver, Canada1, it has proved to be a powerful predictor of the likelihood that a criminal will reoffend.
A qualifying score
To qualify for the empathy study, participants must score higher than 30 on the PCL-R scale, out of a maximum possible score of 40. Qualifiers are told they will participate, but not when ? to give no opportunity to plan escape. On the morning of the test, they are asked to confirm their consent and Meffert goes through the protocol again in more detail. She does not, however, explain the detailed scientific aims of the study in case the subjects try to manipulate the outcome.
Inside the clinic, Meffert is often alone with her subjects but wears an alarm around her neck. ?Once I pressed it by accident and was amazed to find myself surrounded by several guards who seemed to spring from nowhere within seconds,? she says. ?I feel safe.? Meffert is a calm person, who works well with her subjects by talking and listening to them seriously. But she says that psychopathic people can be very tiring to work with because they command, and need, intense attention.
On the morning of his test-day interview, patient 13, although taken by surprise, is looking what must be close to his best. His hair and beard are fashionably trimmed, and his clothes are casual but coordinated. Walking to the small interview room, he says he wishes he had more notice, but he is laughing. He listens to Meffert's detailed explanation of how the day will run and gives his agreement.
An hour later he is on the road, in an armoured van. No metal is allowed near the scanner. Even his tattoos nearly ruled him out as a subject, but they are small, and also recent enough that the red in them is likely to be from newer, iron-free dyes that won't affect the imaging. The guards don't carry guns, the rod fitted down patient 13's trouser leg, preventing him from running, is security enough. Handcuffs are made of a special non-metal material.
Patient 13 doesn't seem to think much of the experiment itself. The sequence of film clips, which are projected inside the scanner directly above his face, only run for ten minutes or so. But he finds it hard to concentrate and his eyelids, observed remotely by the researchers in the adjacent control room, begin to droop. Meffert runs the clip again ? the experiment requires the subject's full attention.
Most of the others who have taken part in the study were much more compliant and easier to handle in the scanner than patient 13 ? often they are more cooperative than the average student volunteer, says Meffert. All the subjects seemed to find the experiment to be nonsense. ?It was stupid, boring,? says inmate Willem Boerema (not his real name), who claims to have taken part only because he likes Meffert. Then, contradicting himself, he adds that ?if they say the study can help people then it's good?.
Boerema, smart, articulate and multilingual, has a PCL-R rating of 35 ? and a big problem with the term 'psychopath'. He views it as a fashionable label abused by the judicial system to keep people like himself from being released. ?The courts look at your PCL-R rating and add two years to your sentence, then another two years, and then another.?
I think my high psychopath score is a talent, not a sickness. Willem Boerema
When he entered the prison five years ago, Boerema says, 'borderline personality' was the fashionable term, and his designated pigeon-hole. ?The psychopathy label is more damaging though ? it prompts everyone to see you as a potential serial killer, which I could never be.? (Note, in reporting this article it was agreed that inmates' crimes would be neither asked about nor reported on.) But Boerema also wears the score as a badge of honour: ?I think my high psychopath score is a talent, not a sickness ? I can make good strong decisions, and it's good to have some distance with people.?
Some psychopathic features are not necessarily a bad thing for society ? in some professions they may even help. Robert Hare
There is some truth in this, says Hare. As well as developing the PCL-R, he has also developed a shorter version suitable for screening the general population (PCL-SV, with the SV standing for screening version). He has used it to estimate that maybe 1% are psychopathic, even if they have never committed a crime, according to research presented recently at a meeting on psychopathy research. ?Some psychopathic features are not necessarily a bad thing for society ? in some professions they may even help,? says Hare. ?Too much empathy, for example, on the part of a police officer or a politician would interfere with the job.?
In theory, scientists like Keysers could recruit high-scoring psychopaths from the general population as control subjects for studies on empathy. But identifying enough of them would be extremely time consuming. Some scientists without access to the captive population in prisons ? a fifth of whom may be psychopathic according to Hare2 ? have turned to populations on the outside with specific behavioural problems.
Neuroscientist Jorge Moll, for example, from the Labs-D'Or Hospitals network in Rio de Janeiro, Brazil, screened and recruited 'troublesome' outpatients of a civil psychiatric centre for his ongoing neuroimaging study to identify the neural circuits involved in moral judgement. Drug use, which can interfere with results, is a bigger hazard in those outside prisons than those inside, he concedes, ?but the standards of security in Brazil don't make a prison study feasible here?.
James Blair at the National Institutes of Health in Bethesda, Maryland, gets around the drug problem by using children with behavioural problems who score highly on the PCL-SV rating, and whose parents have responded to his advertisement. Kent Kiehl, now at the University of New Mexico in Albuquerque, has worked with parole populations in Connecticut, but found the subjects so unreliable that he spent three-quarters of his time getting them to keep appointments. New Mexico is one of several US states that, like the Netherlands, are keen to promote psychopathy research. Kiehl has made the most of the supportive environment and developed a mobile fMRI machine to conduct a dozen or so different studies ? from empathy and moral reasoning to cognitive function ? on 300 inmates. ?Going into the prison means you can get many more subjects than would be possible by bringing them out individually with all the arrangements that requires,? he says. ?Larger subject numbers mean a more definitive study.?
All of these psychopathy researchers believe that their work will lead to a level of understanding of the condition that could eventually lead to a treatment. Keysers does too ? even though his prime motivation in recruiting psychopaths was to support his empathy research. He now finds himself ?fascinated by the phenomenon of the untreatable psychopath?, and also convinced that there will one day be a fix. Patient 13, meanwhile, has finished his test day wearing the same smile he set out with. If a form of therapy were ever to emerge, it is not clear whether people like him ? who do not consider themselves sick ? would be willing to take it.
Hare, R. D. in The International Handbook of Psychopathic Disorders and the Law (eds Felthous, A. & Sass, H.) 41?67 (John Wiley, Chichester, UK, 2007).
Hare, R. D. Manual for the Revised Psychopathy Checklist 2nd edn (Multi-Health Systems, Toronto, Ontario, Canada, 2003).
Keysers, C. & Gazzola, V. Prog. Brain Res. 156, 379?401 (2006).
Alison Abbott is Nature's Senior European Correspondent.
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Abbott, A. Abnormal neuroscience: Scanning psychopaths. Nature 450, 942–944 (2007). https://doi.org/10.1038/450942a