Excited Delirium, Policing, and the Law of Evidence

By OSAGIE K. OBASOGIE

Police use of force continues to be a significant problem in American law and society. Recent discussions have focused on doctrinal issues such as what type of force is considered “reasonable” under the Fourth Amendment and the propriety of qualified immunity as a defense that can shield law enforcement from civil litigation. However, there has been little commentary on how these and other legal questions might be informed by medicine — specifically, victim diagnoses that might effectively absolve officers from criminal prosecution or civil liability. One prominent example concerns excited delirium, which is thought to be a psychiatric issue characterized by the acute onset of extreme agitation that can become so severe that someone might die spontaneously, on their own, without anyone to blame except the person’s own mental condition. This diagnosis has been used by coroners, medical examiners, forensic pathologists, and law enforcement to suggest that some deaths in police custody occur not because the decedent was subject to unlawful force, but because the mysterious onset of a psychiatric illness led them to die suddenly. But there are significant problems with this claim. Notably, since its inception in the 1980s, researchers have found little evidence that this medical condition exists. This lack of proof leads to a critical question: How did law become so welcoming to excited delirium when medical and scientific communities continue to have serious reservations? This Article provides the first empirical assessment of how excited delirium has been treated as an evidentiary matter within federal courts. In doing so, it explores how federal courts deploy Federal Rule of Evidence 702 to understand the claims made by expert witnesses in cases regarding the admissibility of excited delirium as a medical diagnosis that might explain deaths in police custody. The findings show that excited delirium often enters evidentiary proceedings as a contested medical concept. Yet, through the machinations of the law of evidence, these claims exit courtroom proceedings as legally relevant facts. How this transmutation happens, and the evidentiary moves that make it possible, highlight the extent to which legal doctrine can settle an otherwise unsettled — if not wholly discredited — area of medicine to make deaths in police custody seem natural, blameless, and unproblematic. Understanding how the law of evidence contributes to concealing what might otherwise be seen as unreasonable uses of force is critical for ongoing discussions concerning police reform.

Harvard Law Review, VOLUME 138, ISSUE 6, APRIL 2025, 26p.