In-Custody Deaths, Toxicology, and the End of Excited Delirium in California
Excited delirium in California may no longer be used as a diagnosis, cause of death, or evidence in a civil action. The toxicology arguments that once supported the label still require exacting scrutiny.
Excited delirium in California once supplied a ready-made explanation when a person died during police restraint. For decades, the label appeared in death records and carried an implicit theory of causation: an agitated physiological state—often attributed to drugs—caused the death, while the restraint was incidental. California law now rejects that label as a valid medical diagnosis or cause of death.
Key points
- AB 360 bars the diagnosis. California does not recognize excited delirium as a valid medical diagnosis or cause of death.
- The term is inadmissible in civil actions. Evidence Code section 1156.5 excludes evidence that a person suffered or experienced excited delirium.
- Facts remain admissible. Witnesses may describe agitation, conduct, and physical or mental condition, but may not attribute those observations to the prohibited label.
- Toxicology does not replace causation analysis. A detected drug or postmortem concentration must be evaluated with the specimen source, analytical records, autopsy, restraint mechanics, and timeline.
Assembly Bill 360, signed in 2023 and effective January 1, 2024, added Evidence Code section 1156.5 and Health and Safety Code sections 24400–24403. A coroner, medical examiner, physician, or physician assistant may not use excited delirium as the cause of death on a certificate or in a report. A peace officer may not use the term to describe a person in an incident report. And Evidence Code section 1156.5 makes evidence that a person suffered or experienced excited delirium inadmissible in any civil action.
The law’s definition is deliberately broad. It includes “excited delirium syndrome,” “hyperactive delirium,” “agitated delirium,” and “exhaustive mania.” In July 2026, the American Psychiatric Association likewise stated that excited delirium is not a valid diagnosis, lacks validated diagnostic criteria, and should not be used in medical, forensic, or legal settings.
It does not prevent testimony about the factual circumstances. A witness may still describe demeanor, conduct, and physical and mental condition, provided those observations are not diagnosed as—or attributed to—excited delirium.
That distinction is where the litigation now lives. Descriptions of agitation, aggression, or apparent insensitivity to pain may be admissible. The label that converted those observations into a medical condition or cause of death is not.
The toxicology that supported the label
The excited-delirium theory often relied on a positive postmortem toxicology result, particularly for a stimulant. The reasoning was that the drug explained the agitation, the agitation explained the physiological collapse, and the restraint was therefore incidental. Each step requires independent proof.
- Concentration does not establish behavior. Fatal and nonfatal stimulant concentrations can overlap, and a postmortem value does not show what a person was doing, perceiving, or capable of at a particular moment.
- Postmortem redistribution can alter results. A concentration measured after death is not automatically equivalent to the circulating concentration before death. Interpretation depends on the drug, specimen type, collection site, postmortem interval, and storage history.
- Tolerance affects concentration–effect relationships. The same concentration can have different effects in different people. Postmortem chemistry alone cannot quantify an individual’s tolerance.
- Agitation is not drug-specific. Fear, pain, psychiatric crisis, delirium from recognized medical causes, hypoxia, and metabolic disturbance can also produce agitation. Some may arise before restraint; others may develop during the encounter.
A drug in the blood is not, by itself, a mechanism of death. It is one piece of evidence that must be tested against the mechanical and temporal facts of the encounter.
What replaces the label
Removing a conclusory label does not decide causation. It returns the analysis to the evidence: the position and duration of restraint, the location and duration of applied weight or pressure, the interval to loss of responsiveness or pulse, airway and chest-wall movement, physiologic data, and what body-camera recordings and dispatch audio establish.
What to assemble early in an in-custody death case
- The complete autopsy protocol, photographs, histology, specimen inventory, and documented sampling sites.
- The complete toxicology packet—including methods, chromatograms, calibrators, controls, uncertainty information, and chain of custody—not merely the summary values.
- Every body-worn-camera and vehicle-camera file in native format with original metadata.
- Dispatch and radio audio with synchronized timestamps to establish the sequence and duration of events.
- Training materials and policies on restraint, prone positioning, monitoring, and medical response that were in effect at the time.
- Evidence of prior similar incidents relevant to notice, policy, custom, training, or supervision.
Why toxicology expertise matters in a civil-rights case
In a section 1983 wrongful-death or excessive-force case, medical and legal causation may be central. When the defense theory is physiological, the factfinder needs a disciplined explanation of what a postmortem concentration does—and does not—show. The goal is not to claim that drugs were irrelevant. It is to prevent a laboratory number from standing in for a proven mechanism of death.
The Okorocha Firm handles civil-rights matters and provides retained forensic toxicology expert-witness services in cases tried by other firms. Related reading includes our discussion of postmortem toxicology and redistribution and our overview of forensic toxicology.
Frequently asked questions
Is excited delirium admissible in a California civil action?
No. Evidence Code section 1156.5 makes evidence that a person suffered or experienced excited delirium inadmissible in a civil action. Witnesses may describe the underlying facts, but they may not attribute the person’s demeanor, conduct, or condition to excited delirium.
Can witnesses still describe how the person was behaving?
Yes. Witnesses may describe demeanor, conduct, and physical and mental condition, including agitation or aggression, as long as they do not diagnose or attribute those observations to excited delirium or the alternative terms covered by the statute.
Does a positive drug test explain an in-custody death?
Not by itself. A postmortem drug concentration does not establish a person’s behavior or a mechanism of death. Interpretation requires the sampling site, postmortem interval, analytical records, tolerance evidence, autopsy findings, restraint evidence, and event timeline.
What did California Assembly Bill 360 change?
AB 360 bars excited delirium as a valid medical diagnosis or cause of death in California, prohibits specified official uses of the term, and added Evidence Code section 1156.5 to exclude excited-delirium evidence in civil actions.
What evidence matters in an in-custody death investigation?
Important evidence includes the complete autopsy and toxicology files, specimen collection sites, body-camera and vehicle-camera recordings with metadata, dispatch audio and timestamps, restraint positions and duration, weight or pressure applied, training materials, and prior similar incidents relevant to policy or custom.
Sources and further reading
- California Assembly Bill 360 (Stats. 2023, ch. 431), chaptered bill text.
- California Evidence Code section 1156.5, current statutory text.
- California Health and Safety Code sections 24400–24403, current statutory text.
- American Psychiatric Association, Position Statement on Use of the Term “Excited Delirium” (2026).
- Logan BK, Fligner CL, Haddix T. Cause and manner of death in fatalities involving methamphetamine. J Forensic Sci. 1998;43(1):28–34.
- Ferner RE. The toxicological significance of post-mortem drug concentrations in bile. Clin Toxicol. 2018;56(1):7–13.
- Weedn VW, Steinberg A, Speth P. Prone restraint cardiac arrest in in-custody and arrest-related deaths. J Forensic Leg Med. 2022;89:102354.
- Michalewicz BA, Chan TC, Vilke GM, et al. Ventilatory and metabolic demands during aggressive physical restraint in healthy adults. J Forensic Sci. 2007;52(1):171–175.
This article provides general information about forensic science and California law. It is not legal advice, and reading it does not create an attorney-client relationship. Verify authorities and record-specific facts before relying on them in litigation.
