More That Officers Should Know About High-Risk ExDS Encounters

Print Friendly, PDF & Email

In reporting another new study of excited delirium, researcher Dr. Darrell Ross offers additional insights for improving the safety of officers and subjects alike in these fraught confrontations.

The goal is not to train or expect officers to make clinical diagnoses in the field as psychiatric experts, Ross says. “But providing them with research findings can enhance their awareness and focus to properly direct their initial response and use-of-force control measures.”

In addition, officers’ recognition of subjects’ key behavioral symptoms can help EMS personnel choose appropriate medical intervention. And “should a death occur,” Ross writes, “officer observations can assist investigators and the medical examiner in assessing contributing factors.”

Ross of Valdosta (GA) State U. and his co-author Dr. Michael Hazlett of Western Illinois U. analyzed UOF reports of 635 violently resistant arrestees who exhibited symptoms of excited delirium syndrome [ExDS], as compiled by 17 police departments and sheriff’s agencies in six US states.

Here are highlights they think officers should know in preparation for a potential encounter:


Beyond violent behavior per se, which of course is not unique to ExDS situations, the new study identifies 12 telltale symptoms associated with the syndrome that officers can readily recognize: the 10 listed by Baldwin’s team in Item I above plus “incoherent speech” and “bizarre behavior.”

The most commonly confronted overall during the study period tended to be non-responsiveness to police…high pain tolerance…hyperactivity…incoherent speech…and extreme strength. Least common was attraction to glass (“rarely reported”). Nearly 60% of the subjects studied exhibited three to four ExDS symptoms, with 12% displaying seven to 10. No one displayed all 12.

Those in the seven-or-more category were significantly more likely to exhibit the most dangerous qualities, including extreme strength and unflagging stamina, high-pain tolerance, hyperactivity, bizarre behavior, and non-responsiveness. Those subjects were also most likely to be hot to the touch, fully or partially nude, sweating profusely, and breathing rapidly.
RESISTANCE. Simply stated, Ross writes, the greater the number of ExDS symptoms displayed, the higher the level of arrestee resistance—similar to what Baldwin and his team found. Ross describes three potential gradations of intensity

  • defensive resistance, such as pulling, prying, twisting, stiffening, or running away—actions “meant to defeat the officer’s efforts of control and not intended to harm”;
  • active resistance, where the arrestee uses personal weapons (grabbing, wrestling, punching, kicking) to physically assault the officer;
  • aggravated active resistance, severe felonious attacks with personal or other weapons that “may seriously injure or kill the officer.”

Overall, he explains, 75% of subjects exhibiting three to four symptoms presented defensive resistance. Those in the five- to six-symptom group resorted to active resistance more frequently (85% in that category did so), and those showing seven or more symptoms “were more likely to escalate” to active (75%) or aggravated (25%) attacks.

Even after being put on the ground in a prone position, about one-third of subjects showing five or more symptoms continued to present active or aggravated resistance, Ross finds.

At every level, “the behaviors and the type of resistance demonstrated by persons in excited delirium is unpredictable,” he states, “and officers must remain alert to protecting themselves as well as the arrestee throughout the interaction.”


To establish control, a conducted energy weapon [CEW] was used about 40% of the time against individuals showing five or more symptoms and assaultive behavior, Ross reports.

On average, two trigger pulls were needed to bring the assailant down, with the CEW typically discharged once more if resistance continued even after the subject was in a prone restraint position.

The weight of one or two officers was placed on the back of a grounded subject for one to five minutes in about 90% of the cases, and arrestees were hobbled in about one-third of the incidents—tactics that some critics have argued are potentially deadly for subjects.

To the contrary, Ross stresses, none of the study subjects died regardless of the force measures used—“a significant finding.” Arrestees did not sustain any injury about 80% of time and suffered serious injury (such as broken or dislocated bones or head trauma) in only 3% of instances. “A high percentage of arrestee injuries resulted from their violent resistance,” he says.

Ross and Hazlett devote significant space in their paper to discussing the desirability of employing a CEW to control subjects exhibiting five or more ExDS symptoms.

“While there is no risk-free use of force device or technique,” they state, “scientific research consistently shows that the CEW reduces the risk of injury or death with arrestees…. [A]rrestees exhibiting symptoms of ExDS are generally impervious to pain and the CEW provides a viable and safe use of force response to overcome [their] combative behaviors.”
In short, the study supports the conclusion of other researchers that a CEW is “the preferred [nonlethal] use-of-force device when faced with violent and agitated arrestees.”


Ross urges that agencies provide training on ExDS to “officers, dispatchers, administrators, emergency medical personnel, and investigators.” By policy, he says, these stakeholders, along with mental health professionals, should train together to coordinate an effective response to ExDS emergencies whenever feasible.

He recommends that a checklist of symptoms be provided to dispatchers so they can “obtain as much information as possible about [a subject’s] behaviors when dispatching officers to the scene.” Once there, officers should apply force measures, control, and restraint “quickly to minimize the arrestee’s exertional activity and shorten the confrontation,” he advises.
The symptom checklist should also “be embedded into the department’s response-to-resistance report form, so officers can fully document” their observations, as well as their verbal and physical attempts at control.
A full report on the study, titled “Assessing the symptoms associated with excited delirium syndrome and the use of conducted energy weapons,” is published in the Forensic Research & Criminology International Journal. It can be accessed free of charge by clicking here.

Dr. Ross, a professor and department head for sociology, anthropology, and criminal justice at Valdosta State, can be reached at: dross@valdosta.edu

Leave a Reply


  • Privacy Policy

Privacy Policy

Effective date: January 06, 2019

Force Science Institute, Ltd. (“us”, “we”, or “our”) operates the https://www.forcescience.org/ website (hereinafter referred to as the “Service”).

This page informs you of our policies regarding the collection, use, and disclosure of personal data when you use our Service and the choices you have associated with that data. Our Privacy Policy for Force Science Institute, Ltd. is based on the Privacy Policy Template from Privacy Policies.

We use your data to provide and improve the Service. By using the Service, you agree to the collection and use of information in accordance with this policy. Unless otherwise defined in this Privacy Policy, the terms used in this Privacy Policy have the same meanings as in our Terms and Conditions, accessible from https://www.forcescience.org/

Information Collection And Use

We collect several different types of information for various purposes to provide and improve our Service to you.

Types of Data Collected

Personal Data

While using our Service, we may ask you to provide us with certain personally identifiable information that can be used to contact or identify you (“Personal Data”). Personally identifiable information may include, but is not limited to:

  • Email address
  • First name and last name
  • Phone number
  • Address, State, Province, ZIP/Postal code, City
  • Cookies and Usage Data

Usage Data

We may also collect information on how the Service is accessed and used (“Usage Data”). This Usage Data may include information such as your computer’s Internet Protocol address (e.g. IP address), browser type, browser version, the pages of our Service that you visit, the time and date of your visit, the time spent on those pages, unique device identifiers and other diagnostic data.

Tracking & Cookies Data

We use cookies and similar tracking technologies to track the activity on our Service and hold certain information.

Cookies are files with small amount of data which may include an anonymous unique identifier. Cookies are sent to your browser from a website and stored on your device. Tracking technologies also used are beacons, tags, and scripts to collect and track information and to improve and analyze our Service.

You can instruct your browser to refuse all cookies or to indicate when a cookie is being sent. However, if you do not accept cookies, you may not be able to use some portions of our Service. You can learn more how to manage cookies in the Browser Cookies Guide.

Examples of Cookies we use:

  • Session Cookies. We use Session Cookies to operate our Service.
  • Preference Cookies. We use Preference Cookies to remember your preferences and various settings.
  • Security Cookies. We use Security Cookies for security purposes.

Use of Data

Force Science Institute, Ltd. uses the collected data for various purposes:

  • To provide and maintain the Service
  • To notify you about changes to our Service
  • To allow you to participate in interactive features of our Service when you choose to do so
  • To provide customer care and support
  • To provide analysis or valuable information so that we can improve the Service
  • To monitor the usage of the Service
  • To detect, prevent and address technical issues

Transfer Of Data

Your information, including Personal Data, may be transferred to — and maintained on — computers located outside of your state, province, country or other governmental jurisdiction where the data protection laws may differ than those from your jurisdiction.

If you are located outside United States and choose to provide information to us, please note that we transfer the data, including Personal Data, to United States and process it there.

Your consent to this Privacy Policy followed by your submission of such information represents your agreement to that transfer.

Force Science Institute, Ltd. will take all steps reasonably necessary to ensure that your data is treated securely and in accordance with this Privacy Policy and no transfer of your Personal Data will take place to an organization or a country unless there are adequate controls in place including the security of your data and other personal information.

Disclosure Of Data

Legal Requirements

Force Science Institute, Ltd. may disclose your Personal Data in the good faith belief that such action is necessary to:

  • To comply with a legal obligation
  • To protect and defend the rights or property of Force Science Institute, Ltd.
  • To prevent or investigate possible wrongdoing in connection with the Service
  • To protect the personal safety of users of the Service or the public
  • To protect against legal liability

Security Of Data

The security of your data is important to us, but remember that no method of transmission over the Internet, or method of electronic storage is 100% secure. While we strive to use commercially acceptable means to protect your Personal Data, we cannot guarantee its absolute security.

Service Providers

We may employ third party companies and individuals to facilitate our Service (“Service Providers”), to provide the Service on our behalf, to perform Service-related services or to assist us in analyzing how our Service is used.

These third parties have access to your Personal Data only to perform these tasks on our behalf and are obligated not to disclose or use it for any other purpose.


We may use third-party Service Providers to monitor and analyze the use of our Service.

  • Google AnalyticsGoogle Analytics is a web analytics service offered by Google that tracks and reports website traffic. Google uses the data collected to track and monitor the use of our Service. This data is shared with other Google services. Google may use the collected data to contextualize and personalize the ads of its own advertising network.You can opt-out of having made your activity on the Service available to Google Analytics by installing the Google Analytics opt-out browser add-on. The add-on prevents the Google Analytics JavaScript (ga.js, analytics.js, and dc.js) from sharing information with Google Analytics about visits activity.For more information on the privacy practices of Google, please visit the Google Privacy & Terms web page: https://policies.google.com/privacy?hl=en

Links To Other Sites

Our Service may contain links to other sites that are not operated by us. If you click on a third party link, you will be directed to that third party’s site. We strongly advise you to review the Privacy Policy of every site you visit.

We have no control over and assume no responsibility for the content, privacy policies or practices of any third party sites or services.

Children’s Privacy

Our Service does not address anyone under the age of 18 (“Children”).

We do not knowingly collect personally identifiable information from anyone under the age of 18. If you are a parent or guardian and you are aware that your Children has provided us with Personal Data, please contact us. If we become aware that we have collected Personal Data from children without verification of parental consent, we take steps to remove that information from our servers.

Changes To This Privacy Policy

We may update our Privacy Policy from time to time. We will notify you of any changes by posting the new Privacy Policy on this page.

We will let you know via email and/or a prominent notice on our Service, prior to the change becoming effective and update the “effective date” at the top of this Privacy Policy.

You are advised to review this Privacy Policy periodically for any changes. Changes to this Privacy Policy are effective when they are posted on this page.

Contact Us

If you have any questions about this Privacy Policy, please contact us:

  • By email: support@forcescience.org
  • By visiting this page on our website: https://www.forcescience.org/contact
  • By phone number: 866-683-1944
  • By mail: Force Science Institute, Ltd.