Criminal Responsibility
Lack of criminal responsibility due to “legal insanity” is probably one of the most misunderstood concepts in the criminal legal system. Contrary to popular belief, an insanity defense is mounted only in a small number of cases, and of those cases, only a small number are successful. Part of the reason is that, irrespective of the jurisdiction, the legal standard for insanity is difficult to meet. Whereas the legal standard for competency to proceed is relatively low, the standard for an insanity is a demanding one.
This chapter by Professors Lucy Guarnera and Richard Bonnie discusses all aspects of the insanity defense, including identifying mental disorders that may fit into the definition of insanity, through selecting the appropriate expert, understanding the components of an examination such as testing and interviews, and drafting and reviewing the written evaluation. As this chapter emphasizes, the mere diagnosis of a mental disorder in itself is insufficient to constitute insanity; rather, there must be a nexus between the disorder and the conduct charged, or it must, as the authors state, “have significantly altered your client’s perception, rationality, or self-control at the time of the offense to the extent that they grossly misconceived the nature of the situation or were unable to control themselves.”