New Study: Perils & Protections In Dealing With Excited Delirium

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A new study headed by an Advanced Force Science Specialist finds that an officer who confronts a subject in the throes of excited delirium stands nearly a 90% chance of ending up on the ground in a struggle with potentially serious consequences.

The more symptoms of excited delirium a subject exhibits, the greater his likelihood of being violent, researchers report. And more than 40% of afflicted subjects are armed, “generally with weapons of opportunity” such as hammers, shovels, metal bars, pieces of wood, and shards of glass.

Recommendations for how officers can tactically protect themselves and the subjects in these perilous encounters are included in a paper on the study, published recently in the peer-reviewed International Journal of Law and Psychiatry.

“If officers were more aware of the type of danger that could ensue” from excited delirium encounters, “and be better equipped to recognize the features,” the paper says, “then subject and officer injuries could potentially be mitigated.”

The study is believed to be the largest examination yet undertaken of police use-of-force encounters involving probable cases of excited delirium syndrome [ExDS]. The project was led by Simon Baldwin, a PhD candidate in psychology at Canada’s Carleton University and a researcher with the Royal Canadian Mounted Police.

Baldwin carries the highest level of certification in Force Science studies. His five co-authors included two Force Science instructors, Dr. Christine Hall and Chris Lawrence.


The research bored into a four-year collection of force reports amassed by a large Canadian law enforcement agency in a “vast geographical area that includes urban, suburban, rural, and remote communities.” Across that time period nearly 11 million police-public interactions occurred in the area, including 11,237 reported UOF events involving about 9,000 subjects.

The researchers parsed the official force reports in search of probable cases of ExDS, based on the presence of these 10 subject behaviors commonly associated with the syndrome:

  • pain tolerance
  • constant/near constant activity
  • unresponsiveness to police presence
  • superhuman strength
  • rapid breathing
  • lack of fatigue
  • nudity/inappropriate clothing
  • profuse sweating
  • exceptional tactile body heat
  • attraction/destruction of glass.

Of the 9,000 subjects on whom officers applied force, about one in 10 displayed three or more features of ExDS, 156 (1.7%) exhibited six or more, and a “very small number” (0.02%) presented all 10 screening features.
Exhibiting six or more “indicates that an individual is in a highly abnormal state” that can “only be described as a medical emergency” and is considered “probable ExDS,” Dr. Hall explains. Of this group, 95% were male, with an average age of 31, while 88.5% were perceived by involved officers “to be under the influence of drugs and/or alcohol,” with the definite emphasis on drugs. About four in 10 possessed a weapon.

On average, three to four officers responded to the scene to deal with these subjects, “consistent with more dangerous circumstances.”

In day-to-day policing, “individuals with high numbers of features of ExDS are infrequently encountered,” Baldwin notes. But on the statistically rare occasions when force is used—0.08% of police-public contacts—“subjects with multiple features of ExDS are much more commonly encountered.”


Officers confront “highly abnormal, violent subjects” indicative of ExDS “in 1 in every 58 UOF incidents,” Baldwin writes. As the number of ExDS features exhibited by a subject increases, so does the risk of assault.

Subjects displaying six or more of the associated behaviors are more than twice as likely to engage officers in an “assaultive manner” than persons exhibiting less than three features—and nearly four times more likely to present “a threat of grievous bodily harm or death.”

Baldwin notes: “Approximately 88.5% of all probable cases of ExDS engaged in a struggle with an officer that went to the ground…. Compared to those with less than three features of ExDS, the odds of a struggle continuing after going to the ground were nearly three times higher for probable cases of ExDS.”

A struggle going to the ground is significantly different than a subject going to the ground, Baldwin points out. The latter may result from a controlled, multi-officer take-down. “But a struggle going to the ground can have particularly serious consequences for responding officers” as well as for the ExDS subject.

“A prolonged struggle could put these subjects at an increased risk” of arrest-related death because of the intensified physiological stress caused by exertion, Baldwin says. “Officers are also at an increased safety risk, as continued physical resistance by a subject has one of the largest associations with officer injury.”


By definition, Baldwin writes, ExDS subjects “are delirious and unable to make appropriate cognitive decisions” and thus “are unlikely to comply with verbal direction.” Also their pain tolerance, continual activity, and superhuman strength may render interventions that rely on pain compliance or manual force ineffective.

When circumstances permit, the researchers recommend “multiple [officer] responses and effective intervention options to quickly and efficiently control these subjects,” reduce the “extent of struggle involved, and allow for more expedient” medical aid.

CEW probe deployment, for example, provides greater distance from the subject and also tends to have “lower injury rates when compared to the use of physical control,” the study suggests.

Once on the ground, “judicious restraint” should focus on preventing the ongoing use of large muscle groups like the legs, to reduce the adverse physiological effects of continued struggle and minimize the subject’s ability to “generate power” for more resistance. [A number of physical restraint techniques have been developed for controlling ExDS subjects, including one credited to Instructor Chris Lawrence that’s cited in Baldwin’s paper.

For details, see Force Science News #87 at: www.forcescience.org/fsnews/87.html

“Further research is needed, however, to determine which force options optimize outcome for police and subject,” Baldwin states.

“As soon as possible, officers should continuously monitor the subject’s vitals and face” to assess the critical ABCs—airway, breathing, and circulation, the study advises. “Increasing evidence also suggests that prehospital administration of Ketamine” by EMTs “may be an optimal sedative for the treatment of ExDS, due to its quick onset and more complete behavior control,” the researchers say.

In closing, Baldwin emphasizes the importance of recognizing ExDS as a medical emergency, with dispatch of EMS to the scene as early as possible. Regular, up-to-date training on the ExDS phenomenon is urged also, to “guide appropriate policy and response strategies.”

Interestingly, despite ExDS’s deadly (for the subjects) reputation, only four violent afflicted individuals experienced “sudden and unexpected” arrest-related deaths during the study period. Acute stimulant toxicity was documented in all. Baldwin writes: “Numerous co-factors are often involved in [such] deaths, including substance use, mental illness, abrupt cessation of psychiatric medication, poor physical health, psychological and physiological stress, as well as a prolonged struggle.”

The full study, titled “Excited delirium syndrome: Situational factors and risks to officer safety in non-fatal use of force encounters,” can be accessed for a fee by clicking here. A free abstract is available there as well.
Simon Baldwin can be reached at: simonbaldwin@cmail.carleton.ca.

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