Excited Delirium is a condition that I've seen may times during my tenure as a police officer. But, we didn't have a name for it until the past several years. It's a big deal in police work recently (the past two or three years) and officers are being trained on how to recognize it and deal with it. It can be caused by any number of things, including chemical intoxication, and manifests in various ways. But the affected person shows various signs. Extremely irrational behavior, dilated pupils, sweating, often elevated body temperature (which causes them to shed clothing, often being partially dressed, or nude).
The police often get called, because the person may be hyper-aggressive or acting bizarrely. But, excited delirium is more of a medical issue than a criminal issue. But, the police are called because the person is "acting crazy". So, we have to deal with the issue, normally when it is at its height.
The problem is that the subject is often hyper-aggressive, delusional, and has elevated strength. One officer, no matter how competent, fit, or highly trained, is often insufficient to deal with excited delirium. So we call for backup. It normally takes several officers to handle a person with excited delirium. We don't want to hurt the subject, and we don't want to get hurt either. This is more of a medical issue than a criminal prosecution, so we want to be as gentle as we can be. It isn't an easy job.
The other problem is something that the medical and mental health professions are beginning to understand, and that is that these people often die as a result of their delirium. These folks are often fragile, medically, and they exhibit some symptoms (elevated body temperature in the 106-108 range, rapid heartbeat, etc), and when they start coming down, the keep going down, and they die suddenly.
Death is a natural condition. We're all going to die. Lots more people die in hospitals than die in police custody, but you don't hear about the people who die in hospitals. When someone dies in police custody, it is a headline, and it is often assumed to be our fault. Very often, it's not our fault. No police officer wants anyone to die in custody, but it happens.
Excited Delirium is a challenge to police officers nationwide. We've all seen it, and now we're being trained on how to deal with it. That's a good thing, both for the affected person and for the police officer.