A research team led by Force Science faculty member Dr. Christine Hall has brought to light the first reliable statistics in another shadowy and controversial area: the frequency of forceful contact between police and subjects displaying signs of excited delirium syndrome (ExDS).
With five associates, Hall, an emergency medicine specialist and ExDS authority based in British Columbia, analyzed 1,269 consecutive use-of-force events that occurred over a 36-month period during more than 1.5 million police/public contacts in a large Canadian city with nearly 2,000 sworn officers. This study and its ongoing data collection represents the largest database of consecutive general use of force events (including all force modalities) in North America.
In cooperation with the study, officers were instructed to record any evidence of “clinical characteristics” of ExDS that they observed in individuals subjected to use of force beyond “simple escortive techniques.” In other words, as soon as “hard hands” physical and higher levels of force were used, data was collected. Data was collected on all comers not just events with difficult outcome. Officers were given a checklist of “violent behavior, tolerance to pain, constant or near constant physical activity, [unresponsiveness] to police presence, superhuman strength, rapid breathing, [tirelessness] despite heavy physical exertion, naked or inappropriate [clothing] for the environment, sweating profusely, [feeling] hot to the touch, and attraction to or destruction of glass or reflective surfaces.” Officers could check off any number of features, in any combination, or check that “none of the features”. Data collection was contained in normal, in car, use of force reports.
Because it is so common to use-of-force situations apart from any suggestion of ExDS, violence as a “feature of ExDS” was ultimately removed from the researchers’ analysis of ExDS, leaving the 10 remaining features to be assessed.
Nearly 52% of suspects subjected to force displayed none of these flagged behaviors, the study found. But 16.5%—roughly 1 in 6—showed three or more signs of ExDS at the time force was used. The only person who died suddenly in custody during the months surveyed exhibited all 10 ExDS indicators, according to officers’ reports. While this is a small number of people in overall policing across all calls when situations involve use of force, consideration of Excited Delirium becomes much more important.
“It should be noted that not all individuals with large numbers of concomitant clinical signs of ExDS had all the same signs,” the researchers report. In other words, there did not seem to be a single central core group of indicators. Also, with only one death occurring out of the large sample, the team concluded that “we cannot comment on causality or correlation between number of Excited Delirium signs and mortality.”
An important aspect of this study is that giving officers a checklist of features to be aware of does not compel them to find those things present. 83.5% of subjects undergoing use of force had few if any features of ExDS recorded as present at the time force was used. This is important in offsetting the criticism that teaching officers about Excited Delirium causes them to find it in everyone. Hall found that is not the case.
The researchers consider that determining the incidence of ExDS in force encounters is an important step in starting to unravel the mysteries of this rare but perplexing phenomenon. Among other things, they hope that future studies (and the study is ongoing) will illuminate whether higher number of ExDS indicators can predict a suddenly fatal outcome and specifically which symptom or cluster of cues may be associated.
As a byproduct of their principal research, the team confirms that use of force by LE is a relatively infrequent occurrence. Of the 1.5 million police-public face to face interactions that occurred during the study interval, 99.92% did NOT involve a use of force response. This number has been stable across three years of study to date.
A full report of the study appears in the Journal of Forensic and Legal Medicine. Click here to access a free abstract.