Until recently, our inner mental lives have enjoyed a considerable degree of natural protection from others’ gaze and influence. Third parties are sometimes able to attribute particular mental states to us on the basis of our behaviour, particularly if they know us well. These parties are also often able to influence our mental states by means of rational persuasion or manipulation. But our thoughts, desires and emotions have typically had some defence against others’ access and influence by virtue of the fact that these mental phenomena play out in our brains, shielded by a solid skull.

As discussed in Chapter 1, the primary focus of this book is on the potential of neurotechnology to support the rehabilitation of convicted persons by improving risk assessment and risk management – rather than on its potential for diagnosing and treating mental or brain disorders. Still, in some cases, neurorehabilitation might well become conducive or even crucial to the improvement of mental health in forensic populations. Brain stimulation to attenuate aggressive impulses might serve to reduce the mental distress experienced by some persons subject to these impulses. Furthermore, aggression can be a symptom of a recognised mental illness, such as a psychotic disorder, or may be a core feature of a disorder, as in intermittent explosive disorder. Diminishing aggression using neurotechnology could in such cases be relevant to the person’s mental health, which appears to be an interest protected by human rights law. For example, Article 12 of the International Covenant on Economic, Social and Cultural Rights (ICESCR) recognises a “right to the highest attainable standard of physical and mental health”.