Criminal offenders may be offered to participate in voluntary rehabilitation programs aiming at correcting undesirable behaviour, as a condition of early release. Behavioural treatment may include direct intervention into the central nervous system (CNS). This article discusses under which circumstances voluntary rehabilitation by CNS intervention is justified. It is argued that although the context of voluntary rehabilitation is a coercive circumstance, consent may still be effective, in the sense that it can meet formal criteria for informed consent. Further, for a (...) consent to be normatively valid (“take the wronging out of the act”) under a coercive circumstance, the subject to be treated must (1) have the sovereign authority to consent, and (2) the offer-giver must be in the right normative position to make the offer. While I argue that subjects do have the sovereign authority to consent to treatment, I also argue that inappropriate offers yield invalid consents. Considerations on inappropriate offers should therefore inform which kinds of CNS intervention-based rehabilitation schemes the state may propose as part of the criminal justice system. Yet as I conclude in this paper, while there are some intrinsic constraints on voluntary rehabilitation programs, the main constraints on voluntary rehabilitation are likely to be contingent overriders. However, CNS intervention is not ruled out as such in the context of voluntary rehabilitation. (shrink)