Acute behavioural disorder


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Page last updated: 20/11/2022

Acute behavioural disorder

In this brief guide, we will discuss Acute behavioural disorder.

What is Acute Behavioural Disorder?

Acute Behavioural Disorder (ABD) is a medical emergency. It is also known as ‘Excited Delirium’ or Acute Behavioural Disorder.

There is currently no consensus on the definition of ABD, however, the College of Paramedics recognizes the definition suggested by the Royal College of Emergency Medicine, according to which ABD is a “sudden onset of aggressive and violent behaviour and autonomic dysfunction”. 

Nevertheless, there is no standardized definition 

The accepted terminology: Acute Behavioural Disturbance (ABD) is adopted by the UK Police Forces, the Ambulance Services and the Faculty of Forensic and Legal Medicine. 

Physical symptoms of Acute Behavioural Disorder:

  • Extremely aggressive/violent behaviour, 
  • Insensitive to pain, 
  • Excessive strength/continued to struggle despite restraint,  
  • Hot to touch/profusely sweating/inappropriate state of undress, 
  • Acute psychosis with fear of impending doom,  
  • Constant physical activity without fatigue, 
  • Hyperthermia,  
  • Tachypnoea(excessively rapid respiration),
  • Tachycardia.

The aims of rapid tranquilization in the case of Acute Behavioural Disorder are threefold:

  • To reduce further psychological and physical suffering for the patient,
  • To reduce the risk of harm to others,
  • To not harm.

Acute behavioural disorder

Management with an individual with Acute Behavioural Disorder


Physical or manual restraint should be an intervention of last resort before providing definitive chemical restraint or rapid tranquilization.

Long physical restraint is forbidden.

Sedation or rapid tranquilization

Rapid tranquilization is needed if the individual with Acute Behavioural Disorder doesn’t respond to de-escalation techniques. 

The absorption of Intramuscular injection medication can be faster when an individual is agitated or physically overactive.

Individuals displaying Acute Behavioural Disorder may need much higher doses of sedative agents than are usually required.

Three groups of agent used for sedation in Acute Behavioural Disorder are benzodiazepines, ketamine, and antipsychotics.

Supportive Management in a hospital 

After sedation must be a physical examination with documentation of the individual’s temperature, standard laboratory investigations for the health of the individual. 

Lorazepam for Acute Behavioural Disorder

If rapid tranquilization is considered necessary, and where there is any uncertainty about previous medical history, uncertainty regarding current medication, or the possibility of current illicit drug/alcohol intoxication, lorazepam is the drug of choice.

The dosage should be the minimum necessary to achieve the desired effect.

NICE guidance recommends IM lorazepam as the first line.

Appropriate adjustments to the dosage should be made in the case of detainees who are children, young persons, or elderly.

Where the detainee is unresponsive to the maximum British National Formulary recommended dose, it may be more preferable and safer to consider a transfer to a hospital than to prescribe over the recommended maximum. 

There are specific risks connected to the use of lorazepam:

  • Loss of consciousness,
  • Cardiovascular collapse,
  • Paradoxical excitation.
  • Respiratory depression or arrest
  • Disinhibition.

Recommended sources and books:

  1. HFNE
  2. Accessing the Healing Power of the Vagus Nerve: Self-Help Exercises for Anxiety, Depression, Trauma, and Autism
  3. Acute Stress Disorder: A Handbook of Theory, Assessment, and Treatment
  4. I Hate You–Don’t Leave Me: Understanding the Borderline Personality
  5. Personality Disorders


This brief guide helped us to know that Acute Behavioural Disorder is a sudden onset of aggressive and violent behaviour and autonomic dysfunction.

It presented physical symptoms that refer to ABD and showed us the steps for the management with an individual with Acute Behavioural Disorder.

In these cases can be used lorazepam but don’t forget to pay attention to the mentioned risk of the use.


  1. Disorder in healthcare
  2. Guidelines for the Management of Excited Delirium / Acute Behavioural Disturbance (ABD)
  3. Hyperthermia: Symptoms, treatment, and causes
  4. Mental health art 
  5. Tachycardia