Context

There is no widely accepted definition of ABD but it is characterised by a combination of:

• Delirium
• Severe agitation and aggressive behaviour
• Autonomic dysfunction, e.g. hyperthermia

It is usually associated with illicit drug use and patients are often accompanied by, and/or being restrained by, the police.

The RCEM Best Practice Guideline¹ on Acute Behavioural Disturbance describes ABD as a clinical picture with various potential causes and presenting features, it should not be considered a diagnosis or syndrome.

It may proceed to metabolic acidosis, rhabdomyolysis, multi-organ failure and death.

There is little data on the true incidence of ABD as:

• There are no clear diagnostic criteria
• Due to publication bias, most reported cases involve those that died; little is known about how many patients experience ABD but survive, and why.

The typical case of ABD in the media involves a young man with acute drug intoxication, physical restraint by law enforcement officers and sudden death. As a result, such deaths have historically been attributed to acute drug toxicity or police brutality. It is therefore vital to enhance understanding of the process of ABD to ensure its correct diagnosis and management to avoid situations where blame may otherwise be placed on law enforcement officers. Both JRCALC and the College of Policing have issued specific guidance on ABD.

Police training on ABD includes minimising restraint time, avoiding restriction of breathing, attempting to de-escalate where possible, to call for an ambulance. Guidance states that police should bring the patient to an ED for assessment rather than detaining them under police custody.

The Royal College of Psychiatrists released a Position Statement² in 2022 titled Acute Behavioural Disturbance and Excited Delirium.

Learning Bite

Due to the lack of a universal definition of ABD it is difficult to know its exact incidence, but evidence suggests the mortality rate in those experiencing ABD could be up to 14%.³