Can a novel scientific method provide evidence of torture?

By Paula Suárez-López

How can torture survivors prove that they have been tortured when there are no physical marks left in their bodies? During the last decades, torturers are increasingly using psychological torture and physical torture methods that hardly leave any visible physical sign. Prolonged solitary confinement, sleep deprivation, positional stress, constant loud noise and waterboarding, widely used by the US in the context of the war on terror and by other countries around the world, are just five examples of this. Despite not leaving marks, these forms of torture cause extreme mental and sometimes physical suffering and often have devastating consequences for the survivor’s mental health. To obta in justice and reparations, torture survivors need something to show. Psychological assessments can be very helpful, but often are not sufficient. Is it possible to find biological markers of torture that support torture allegations? In a recent article in the Torture Journal, entitled ‘The potential of epigenetic methods to provide evidence of torture’, I propose to test a novel approach, based on state-of-the-art molecular biology methods, to this effect.

Trauma is associated with changes in the DNA

 There is mounting evidence that trauma, such as childhood abuse or war-related trauma, is associated with certain changes in the genetic material, the DNA. These changes, called epigenetic changes, do not alter the genetic information carried by DNA. They alter epigenetic marks, which are tags that are added to, or removed from, the DNA to modulate gene activity. Changes in these marks make genes either more active or less active. Epigenetic changes occur naturally and are often a natural response to environmental influences, such as temperature or nutrition. The term “molecular scars” has been used for these changes when they are associated with trauma or stress. Now the question is whether torture, an extreme form of trauma, leaves molecular scars in the DNA. Although this can be very difficult to prove, my article argues that it is worth testing whether torture is associated with changes in epigenetic marks, because, if this were the case, perhaps detecting these changes might contribute to support allegations of torture in the future. This would be a breakthrough.

Limitations of epigenetic methods

But this road is not an easy one. Even if they work, epigenetic methods will not be a silver bullet. The article, does not argue that epigenetic methods will provide irrefutable proof of torture. What it argues is that, as a first step, it is possible to test whether torture survivors show differences in epigenetic marks relative to people who have not been tortured or people who have experienced other types of trauma. However, the interpretation of the results has to be cautious because an association of torture with epigenetic changes would not necessarily mean that torture causes those changes. Proving this would be much more difficult. Another question is whether epigenetic methods are sensitive enough. The differences in epigenetic marks between traumatised and non-traumatised people are small, usually not bigger than 5 %. Would differences in this range be sufficient to be considered reliable in torture cases? Also, the trauma-related differences have not always been reproducible. And would there be epigenetic changes that are distinctive of torture, as opposed to other types of trauma? All these limitations have to be taken into account when analysing epigenetic marks in torture survivors.

Ethical considerations

Epigenetic experiments with human samples also raise ethical concerns. As any experimentation with human subjects, these experiments must respect all the bioethics principles, which include, among others, avoiding all unnecessary physical and mental suffering; obtaining free and informed consent; and allowing the subjects to withdraw from the experiments or withdraw their consent whenever they wish. Torture survivors can be particularly vulnerable and measures must be taken to avoid re-traumatisation. In addition, privacy and confidentiality must be respected, especially taking into account that some epigenetic methods can reveal the genetic information of the subject.

Advantages of epigenetic methods

Despite all these caveats, epigenetic methods can have advantages when it comes to torture. Particularly promising are results obtained in people subjected to acute sleep deprivation. Compared with individuals who got a full night’s sleep, sleep-deprived subjects showed differences in epigenetic marks in genes related with sleep/wake cycles. Not only does this indicate that stress induces epigenetic changes – something previously shown in animals – it also suggests that certain forms of stress or trauma can be associated with specific changes in epigenetic marks. Let us imagine that torture is associated with epigenetic changes. Then, it would be worth testing whether there are epigenetic changes that are distinctive of certain forms of torture. Moreover, some epigenetic marks are stable and can be detected years after a traumatic event has occurred. There is the possibility that, if torture leaves molecular scars, these can be revealed when other physical signs have already disappeared or never existed.

In sum, the technology to analyse epigenetic marks is available and might be used to determine whether torture is associated with epigenetic changes. Torture survivors, especially those without physical marks of this atrocious human rights violation, are in dire need of proof of their experience. It is a moral imperative to test whether epigenetic methods are useful for this purpose. Finding biological markers of torture would not only help survivors to prove their case and obtain justice, reparation and redress, it would also contribute to preventing torture because it would make potential torturers think twice before inflicting such abhorrent treatment. Other potential benefits would be helping to find new methods to mitigate the effects of torture on the health of survivors and helping to refine the definition of torture. Science can contribute to preventing and prosecuting human rights violations and hopefully epigenetic methods will be a new tool for this purpose.

Paula Suárez-López is a scientist who has made a career change to the human rights field after doing scientific research for three decades. She has a PhD in Biological Sciences and a recent MA in Theory and Practice of Human Rights. She has published her work in various peer-reviewed journals. Currently, her main interest is the use of science to advance human rights.

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