Au cours des dernières années, une explosion d’intérêt pour les neurosciences a conduit au développement du « neurodroit », un nouveau champ de savoir pluridisciplinaire, consacré à l’examen de l’impact et du rôle des découvertes neuroscientifiques dans la procédure judiciaire. Cet engouement a progressivement investi les tribunaux européens et une jurisprudence s’est constituée à l’image des États-Unis, en suscitant des avis divergents. L’association des dysfonctionnements structuraux et/ou fonctionnels du cerveau à la manifestation de certains comportements déviants a ouvert la voie à l’utilisation des neurosciences dans le cadre des expertises pénales et de la psychiatrie légale. En 2011, la France a voté une nouvelle loi qui admet le recours à l’imagerie cérébrale dans le cadre de l’expertise judiciaire. L’introduction des nouvelles provisions légales, spécifiques aux neurosciences, a été décidée sur la base d’un esprit de protection du sujet contre l’usage abusif des neurosciences. Cependant, au regard des évolutions législatives et des pratiques expertales actuelles qui montrent une évolution vers l’évaluation de la dangerosité, il existe un risque que le législateur semble méconnaître : dans le contexte actuel de préoccupation sécuritaire, le juge pourrait avoir tendance à utiliser des données neuroscientifiques introduites par une expertise comme signes de dangerosité, fait susceptible d’entraîner des effets pervers sur le devenir pénal du sujet, dans une visée de protection de la sécurité publique, au détriment de la liberté du sujet.

In the past few years, spectacular progress in neuroscience has led to the emergence of a new interdisciplinary field, the so-called “neurolaw” whose goal is to explore the effects of neuroscientific discoveries on legal proceedings and legal rules and standards. In the United States, a number of neuroscientific researches are designed specifically to explore legally relevant topics and a case-law has already been developed. In Europe, neuroscientific evidence is increasingly being used in criminal courtrooms, as part of psychiatric testimony, nourishing the debate about the legal implications of brain research in psychiatric-legal settings. Though largely debated, up to now the use of neuroscience in legal contexts had not specifically been regulated by any legislation. In 2011, with the new bioethics law, France has become the first country to admit by law the use of brain imaging in judicial expertise. According to the new law, brain imaging techniques can be used only for medical purposes, or scientific research, or in the context of judicial expertise. This study aims to give an overview of the current state of the neurolaw in the US and Europe, and to investigate the ethical issues raised by this new law and its potential impact on the rights and civil liberties of the offenders.

An overview of the emergence and development of “neurolaw” in the United States and Europe is given. Then, the new French law is examined in the light of the relevant debates in the French parliament. Consequently, we outline the current tendencies in Neurolaw literature to focus on assessments of responsibility, rather than dangerousness. This tendency is analysed notably in relation to the legal context relevant to criminal policies in France, where recent changes in the legislation and practice of forensic psychiatry show that dangerousness assessments have become paramount in the process of judicial decision. Finally, the potential interpretations of neuroscientific data introduced into psychiatric testimonies by judges are explored.

The examination of parliamentary debates showed that the new French law allowing neuroimaging techniques in judicial expertise was introduced in the aim to provide a legal framework that would protect the subject against potential misuses of neuroscience. The underlying fear above all, was that this technology be used as a lie detector, or as a means to predict the subject's behaviour. However, the possibility of such misuse remains open. Contrary to the legislator's wish, the defendant is not fully guaranteed against uses of neuroimaging techniques in criminal courts that would go against their interests and rights. In fact, the examination of the recently adopted legislation in France shows that assessments of dangerousness and of risk of recidivism have become central elements of the criminal policy, which makes it possible, if not likely that neuroimaging techniques be used for the evaluation of the dangerousness of the defendant. This could entail risks for the latter, as judges could perceive neuroscientific data as hard evidence, more scientific and reliable than the soft data of traditional psychiatry. If such neuroscientific data are interpreted as signs of potential dangerousness of a subject rather than as signs of criminal responsibility, defendants may become subjected to longer penalties or measures aiming to ensure public safety in the detriment of their freedom.

In the current context of accentuated societal need for security, the judge and the expert-psychiatrist are increasingly asked to evaluate the dangerousness of a subject, regardless of their responsibility. Influenced by this policy model, the judge might tend to use neuroscientific data introduced by an expert as signs of dangerousness. Such uses, especially when they subjugate an individual's interest to those of society, might entail serious threats to an individual's freedom and civil liberties.