ABD – a Medical Perspective

This is the first of a three-part series by a UK Consultant in Emergency Medicine, Dr RS.  The topic of ABD keeps coming up again and again, I was grateful for an offer to get in to some of the detail of all this – debate and discussion is welcome in the comments below.  Parts 2 and 3 in this series will emerge in the next few weeks.


Acute Behavioural Disturbance/Disorder (ABD), formerly referred to as “excited delirium’ is increasingly being recognised within the UK, with concerns raised by police forces, HMP institutions and the media; due to the difficulties in establishing the true rate of occurrence (see later), the unfettered availability of novel psychoactive substances (‘legal highs’) prior to the introduction of specific legislation undoubtedly precipitated a spike in presentations. Arguably the medical response to this rising trend has been sluggish; the Royal College of Emergency Medicine published a guideline on the recognition and treatment of ABD this year (2016).

As with any death in custody (or following police contact), the spotlight focuses on the actions of the officers involved; considerable scrutiny is paid to any use of force employed in an attempt to respond to an individual who is displaying often extremely violent and aggressive behaviour. Controversy exists due to the perception that death is as a result of excessive use of force, and the often negative findings at post mortem to definitively answer why a person suddenly died, leaving relatives with unanswered questions, and police officers subjected to often lengthy investigations, with emphasis on their decision making in the most challenging of circumstances.

The purpose of this BLOG is to increase awareness of the condition, attempt to explain the underlying physiology (limiting medical jargon), treatment options, and necessity of a multi-agency response to individuals exhibiting this life threatening condition. to relevant sources will be made.

Finally, it may be worth explaining my own interest in this subject: I am a medical practitioner working in Emergency Medicine within the UK, with a specialist interest in clinical forensic medicine, psychiatry, and toxicology; I volunteer as a special constable and have prior experience as a Forensic Medical Examiner (police doctor). Over the years, I have personally treated cases of ABD, and seek to increase knowledge dissemination to improve outcomes, but also to recognise the high-risk of mortality associated with the condition.


ABD whilst often described as a relatively new phenomenon, was first reported in a case series by an American psychiatrist in 1849 as “exhaustive mania.” He described a cohort of hospitalised patients exhibiting signs of fever, with extreme agitation, lasting anywhere between hours up to 22 days; death occurred in 75% of cases, with no physical cause found at autopsy.

In 1985, American pathologist Wetli coined the term “excited delirium;” in the Miami region of the USA he noted a pattern that police officers were called to an individual acting strangely, and unresponsive to police instruction. Upon attempting to restrain the person, their behaviour became increasingly violent and aggressive for a short period, followed by sudden collapse and cardiac arrest; resuscitation attempts proved futile. Post mortem findings were limited to injuries of the extremities associated with handcuffs or “hogtie” restraints; toxicological studies were either negative, or levels of cocaine were lower than those found in recreational use. As a consequence of these at-the-time unexplained deaths, civil rights campaigners raised concerns over excessive use of force by the police.

Since Wetli’s publication, there have been further reports of ABD in the medical literature. A variety of recreational drugs have been implicated as the precipitant for the condition, in addition to a limited number of psychiatric illnesses. Theories as to how persons suddenly succumb to the illness, along with postulations relating to the police use of force have been put forward, often with limited evidence or appreciation of the extreme physiology associated; perhaps even more concerning, evidence for suitable treatment options has only recently been published, with clinicians utilising therapies based upon the treatment and care of patients in psychiatric institutions, and ‘what worked in the past.’

In 2009, the American College Of Emergency Physicians published a white paper to formally recognise the diagnosis of Excited Delirium, with suggestions on the management of such patients presenting to the emergency department; in the UK, The Royal College of Emergency Medicine published updated clinical guidelines on Acute Behavioural Disorder in 2016; formal recognition and treatment options are not currently part of a recognised medical curriculum.

UK police force training on ABD (still referred in some areas as excited delirium) is highly varied, ranging from acknowledging its existence in the mandatory officer safety training, to formalised instruction on the disorder.


The role of evidence-based medicine is firmly established with the UK; evidence-based policing whilst in its infancy, is gathering momentum. Critical appraisal of the medical literature reveals the paucity of reliable data available; as an example, a simple search for “diabetes mellitus” in Pubmed will reveal just over 401,500 hits. A similar search for “excited delirium” and “acute behavioural disturbance” will result in under 200 hits. The ‘level’ of evidence as a guide to the quality of publications is limited to case reports/series, with very few prospective evidential data collection; formal randomised controlled trials for the treatment of ABD have been published this year.

A substantial proportion of the literature is published within the forensic pathology field, reflecting the high mortality rate of ABD; the often inconclusive or negative findings at autopsy highlight the lack of a distinct physical terminal event (see part 2). Hampering searches of the literature are the multiple synonyms used to describe ABD: excited delirium, acute exhaustive mania, lethal catatonia, agitated delirium are to name but a few, perhaps indicative of the dispute of what constitutes a diagnosis of ABD.

The collection of robust, statistical evidence to identify the incidence, severity, expected outcome, and success (or failure) of proposed treatment for ABD is notoriously difficult. There are several contributory factors responsible for the impediment of data collection on ABD; not least a specific diagnostic coding for NHS does not exist, police incidents with suspect cases (non-fatal) are hard to discern from the usual ‘angry man,’ and fatal occurrences are investigated by the coroner (England & Wales) or procurator fiscal (Scotland) with limited access to, and data-sharing between, agencies. Further complicating matters, the Independent Police Complaints Commission (IPCC, England and Wales), and Police Investigation and Review Commission (PIRC, Scotland) limit any information until after an investigation has concluded, which may be years from the incident.

The true incidence of the extreme presentation of ABD that is life-threatening is (fortunately) relatively rare; a search of incidents reported to the press that are consistent with death secondary to the condition, reveals any one UK police force has only been subject to at most, one readily identifiable case, (with the exclusion of the Met and Police Scotland, secondary to population and geographical statistics). Given that multiple Emergency Departments are located within such areas, the chance that an individual Emergency Medicine doctor to have experience in the recognition and treatment of the presentation is likely to be extremely low.


The diagnosis of ABD has now been accepted as incorporating three core features:

  1. Delirium
  2. Autonomic disturbance
  3. Violence/aggressive behaviour


Delirium is characterised as an acute confusional state; features consistent with delirium include: inattentiveness, lack of orientation to time/place/person, often coupled with delusional beliefs (extreme paranoia in the context of ABD) and hallucinations (auditory and/or visual). Whilst delirium may result in lower levels of activity, with ABD the person always exhibit agitation, and constant motor activity. This state is responsible for the lack of recognition of emergency services personnel/family members or believing that such people are false or imposters.

Autonomic Disturbance

This feature of ABD refers to the state of the body being a hyper-stimulated state i.e. flight or fight mode, but escalated, and sustained beyond what would normally be experienced. Physiological changes associated with this state include a rapid pulse, elevated blood pressure, elevated body temperature, dilated pupils, flushed skin, and rapid breathing.

Violent Behaviour

As to the behaviour exhibited by individuals in a state of ABD, what is predominantly reported is a sustained aggression towards emergency services personnel, and family members attempting to assist.
The destruction of glass/mirrors has been reported as feature of ABD; however rather than acts of vandalism, this is most likely a result of the altered perception associated with a delirious state. Seeing distorted reflections, such as demons and the like may trigger an attack resulting in the destruction of the reflective surface.
It can be incredibly difficult for emergency services personnel to discern the difference between the statistically more probable ‘angry man’ from an individual exhibiting signs of an ABD.

There is no diagnostic test for ABD; identification is made clinically, from an assessment made observing the patterns of behaviour, a basic assessment of cognitive function, and associated abnormal physiology. What is has become clear, is that ABD is a spectrum of a condition rather than an ‘all or nothing phenomenon’ – appreciation of this is critical to understanding the necessity for early intervention, and the high rate of mortality associated with the extreme presentations faced by police officers.

Part 2 of this series will examine the known triggers for ABD, with an exploration of the underlying physiology associated with the condition.

IMG_0053IMG_0052Winner of the President’s Medal from
the Royal College of Psychiatrists.

Winner of the Mind Digital Media Award.