More than any other defence in the criminal law, the insanity defence has, and continues to be, the subject of heated debate. Yet too little is known about how the insanity defence operates in different jurisdictions, including in the United Kingdom and Ireland. In this book, Mackay and Brookbanks, and their team of expert contributors, explore the theory and practice around the insanity defence and analyse its diverse influence and manifestations across a wide range of common law and civil law jurisdictions. Typically, the insanity defence, as exemplified in the M'Naghten Rules, represents a foundational aspect of criminal responsibility, although in some jurisdictions it serves only to define degrees of mental capacity. However, what all jurisdictions have in common is the high and increasing incidence of mental illness and impairment challenging existing constructions of an exculpatory rule. This book explores in detail the origins and operation of the M'Naghten Rules as well as the eclectic nature of the insanity defence, its highly variable linguistic expression, and the diverse social policy mandates it seeks to embrace. The Insanity Defence will reinvigorate the debate about the defence by discussing both its theoretical basis and exploring how different jurisdictions approach the insanity plea, not only in relation to an appropriate test and how it operates, but also from the perspective of disposal and how those who use the insanity defence successfully are dealt with. This book will be of interest to researchers, academics, and advanced students with an interest in criminal law internationally, as well as to those involved in the development of policy and legislation.

The law relating to fitness to plead is an increasingly important area of the criminal law. While criminalization may be justified whenever an offender commits a sufficiently serious moral wrong requiring that he or she be called to account, the doctrine of fitness to plead calls this principle into question in the case of a person who lacks the capacity or ability to participate meaningfully in a criminal trial. In light of the emerging focus on capacity-based approaches to decision-making and the international human rights requirement that the law should treat defendants fairly, this volume offers a benchmark for the theory and practice of fitness to plead, providing readers with a unique opportunity to consider differing perspectives and debate on the future development and direction of a doctrine which has up till now been under-discussed and under-researched. The fitness to plead rules stand as an exception to notions of public accountability for criminal wrongdoing yet, despite the doctrine's long-standing function in criminal procedure, it has proven complex to apply in practice and has given rise to many varied legislative models and considerable litigation in different jurisdictions. Particularly troublesome is the question of what is to be done with someone who has been found unfit to stand trial. Here the law is required to balance the need to protect those defendants who are unable to participate effectively in their own trial, whether permanently or for a defined period, and the need to protect the public from people who may have caused serious social harm as a result of their antisocial behaviour. The challenge for law reformers, legislators, and judges, is to create rules that ensure that everyone who can properly be tried is tried, while seeking to preserve confidence in the fairness of the legal system by ensuring that people who cannot properly engage in the criminal trial process are not forced to endure it.