Excuse: Insanity

If a person pleads "not guilty by reason of insanity" (NGRI), that plea means that the person committed the underlying act (that would have been criminal had she had the requisite mens rea, or guilty mind), but, because of mental illness, is not to be held responsible for that act. A series of perplexing and difficult questions remains: What should the test be to determine if a defendant is not criminally responsible for her act? If a person is found NGRI, what procedures are to be followed subsequent to the insanity acquittal? And, what do we know about the use of the plea, its success rate, and its implications for those who plead it?

Notwithstanding centuries of jurisprudential evolution, the insanity defense doctrine remains incoherent. Most judges, legislators, scholars, mental health professionals, social policy makers, jurors, journalists, and the public at large would agree with this proposition. This consensus is consistent whether the observer is a retentionist, a modified retentionist, an expansionist, or an abolitionist. Moreover, fixation on questions fundamentally irrelevant to the core jurisprudential inquiry of whom we shall exculpate has resulted in doctrinal stagnation. Immobilized by this irresoluble debate, we continue to ignore even more fundamental questions, such as why we feel the way we do about the "insane" and why, in further structuring the insanity defense, we remain willfully blind to new scientific and empirical realities.

The development of the insanity defense has tracked the tension between psychodynamics and punishment, and reflects our most profound ambivalence about both. On the one hand, we are especially punitive toward persons with mental disabilities who have been charged with crime, characterized by Deborah Scott and her colleagues as "the most despised and feared group in society" (1982); on the other, we recognize that in some narrow and carefully circumscribed circumstances, exculpation is—and historically has been—proper and necessary. This ambivalence infects a host of criminal justice policy issues that involve mentally disabled criminal defendants beyond insanity defense decisionmaking: on issues of expert testimony, mental disability as a mitigating (or aggravating) factor at sentencing and in death penalty cases, and the creation of a "compromise" guilty but mentally ill (GBMI) verdict. And the dissonances, tensions, and ambivalences reflected in insanity defense policy continue to control the public's psyche.

This entry will proceed in this manner. First, it will review the development of substantive insanity defense doctrine, and procedures followed after an insanity acquittal. Next, it will consider the impact of the John Hinckley case on subsequent doctrinal developments. Then, it will examine the empirical myths that underlie much of the insanity defense debate. Finally, it will look briefly at the abolition movement.