Legal Indeterminacy in Insanity Cases: Clarifying Wrongfulness and Applying a Triadic Approach to Forensic Evaluations

Insanity law in the United States embodies a convoluted collection of often ill-defined standards. The wrongfulness test, which is used in most U.S. jurisdictions, requires a determination of whether the accused knew or had the substantial capacity to appreciate that the acts were wrong at the time the accused committed them. To assist the trier of fact in making that determination, courts and parties commonly invoke the acumen of forensic experts. But, wrongfulness in insanity law is a word with many possible meanings.

In this Article, an academic forensic psychiatrist and a legal scholar propose approaches for effectively navigating this legal indeterminacy. The authors parse and clarify key definitions of wrongfulness and provide practical guidance, including an option for a triadic evaluation, for forensic experts called upon to assist the trier of fact in analyzing the complex interface of morality, mental illness, and the law.