Introduction

Brief overview of intermittent explosive disorder (IED)

Intermittent explosive disorder (IED) is a disorder related to aggression, poorly controlled emotions, and outbursts of anger. Initially known as a ‘disorder of impulsive aggression’ from 1952, the understanding and classification of IED have evolved over the years.¹ In general, intermittent explosive disorder (IED) is characterised by recurrent incidents of aggression, seen in the form of verbal or physical aggression towards other people, animals, or property.

Importance of recognising signs and symptoms

The signs and symptoms of intermittent explosive disorder can be distressing to both the person affected by it and those around them. Increased aggression, both physical and verbal, in the person with IED’s immediate environment can cause distress and damage. It can also constrain their involvement and functioning in various areas of their life. By understanding the signs and symptoms of intermittent explosive disorder, effective and targeted support can be offered. 

Definition and diagnosis of IED

Definition of IED

According to the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders), intermittent explosive disorder is defined as recurrent behavioural outbursts representing a failure to control aggressive impulses. It is classified under Disruptive, Impulse-Control, and Conduct Disorders. 

The ICD-11 (International Classification of Diseases) says that the disorder involves brief episodes of verbal or physical aggression or destruction of property. It specifies that the person exhibits an inability to control aggressive impulses where the degree of aggressiveness is out of proportion to the provocation or to psychosocial stressors. 

A study identified and studied IED subtypes based on the type of behaviour during anger attacks, which include people whose anger: 

• Attacks property only
• Attacks threatened people only
• Attacks people and not property
• Destroyed property and threatened people 
• Destroyed property and hurt people ²

Prevalence and causes 

According to a 2006 study of a population of 9282 people above 18 years of age, the lifetime and 12-month prevalence estimates of IED were 7.3% and 3.9%. The mean age of onset was 14 years. In a Turkish sample, the prevalence was higher in people assigned male at birth (AMAB) than in people assigned female at birth (AFAB). IEP is also more prevalent in younger populations (below the age of 35 to 40 years) compared to people over 50 years of age. 

Childhood abuse and exposure to violent behaviour in childhood are major risk factors for developing intermittent explosive disorder.

Diagnostic criteria according to DSM-5

According to the DSM-5, intermittent explosive disorder can be diagnosed by meeting the following criteria:³ 

• IBehavioural outbursts caused by being unable to control aggressive impulses, manifesting either as:
  1. Verbal aggression (temper tantrums, tirades, verbal arguments, fights) or physical aggression (towards property, animals, or other people) that does not result in damage or destruction of property or physical injury to animals or other people. This occurs twice weekly, on average, for 3 months
  2. Three behavioural outbursts involving damage to property and/or physical assault involving injury within 12 months 
• The amount of aggressiveness is out of proportion to what has triggered the aggression
• The aggressive outbursts are impulsive or anger-based and do not have any specific objective like intimidation, power, etc
• The recurrent outbursts cause either distress in the affected individuals or difficulties functioning at work or in relationships
• They can also lead to financial or legal consequences
• A person diagnosed with intermittent explosive disorder must be at least 6 years old
• The cause of recurrent aggressive outbursts is not better explained by any other disorder, a medical condition, or the influence of a substance

Signs and symptoms of intermittent explosive disorder

Aggressive outbursts are a major diagnostic criterion for intermittent explosive disorder. These outbursts can involve: 

• Verbal aggression, such as fights, arguments, shouting, etc 
• Physical aggression, such as attacking property, animals, or other people 

The aggressive outbursts have a rapid onset, lasting typically less than 30 minutes, and occur in response to a minor provocation. The outbursts can be intense and grossly out of proportion to their trigger. 

According to a comparative study of people diagnosed with intermittent explosive disorder (IED) and control populations, a significant difference was seen in the experience, emotions, and consequences of the outbursts exhibited by the people with IED. These included:

• Specific emotions: people with IED reported feeling more enraged, irritated, less clear-headed, more detached, and more afraid or panicked
• Physical sensations: people with IED reported physiological sensations such as hot flashes, racing heart, sweating, and trembling
• A lack of control: people with IED reported feeling more out of control, as well as the urge to scream, hit, or ‘explode’ in anger⁴

The episodes are also associated with significant distress, impairment in social functioning, occupational difficulty, and legal and financial problems. 

Associated features

Intermittent explosive disorder is heavily associated with a poorer quality of life and greater psychosocial impairment. As mentioned earlier, it can interfere with work and relationships, as well as lead to adverse legal and financial consequences. IEDs are also associated with negative health outcomes, including coronary heart disease, hypertension, stroke, etc. Therapeutic interventions and support are therefore needed to help people with IED manage their anger responses to reduce the wider long-term impact of the condition.

Based on the IED subtypes related to anger outbursts and related behaviours, the more violent groups reported higher rates of suicidal behaviour and substance abuse. The less destructive groups reported a higher risk of social phobia and anxiety-related comorbidities.²

Distinguishing IED from other psychiatric disorders

Borderline personality disorder (BPD):

• BPD involves pervasive patterns of instability in interpersonal relationships, self-image, and emotions, along with impulsivity
• In BPD, anger outbursts may be related to fear of abandonment, identity disturbance, or intense mood swings. Unlike IED, the anger outbursts in BPD are typically directed inward (self-injurious behaviours) or may involve manipulation to avoid abandonment

Bipolar disorder

• Bipolar disorder involves mood episodes of mania or hypomania (elevated mood) and depression. While irritability and anger can occur during manic or mixed episodes of bipolar disorder, these episodes are typically longer and accompanied by other manic or depressive symptoms. IED is characterised by sudden, impulsive, and disproportionate anger outbursts that are not necessarily associated with mood episodes

Conduct disorder (CD)

• Conduct disorder is typically diagnosed in childhood or adolescence and involves persistent patterns of behaviour that violate societal norms and the rights of others. While aggression is a common feature of both IED and CD, individuals with IED may have outbursts that are more spontaneous and less planned than the deliberate rule-breaking behaviour seen in CD

Substance-induced mood disorder

• Substance use, particularly drugs or alcohol, can lead to mood disturbances and aggressive behaviour. However, in substance-induced mood disorder, the aggression is directly related to substance intoxication or withdrawal, and the symptoms resolve with abstinence or treatment of the substance use disorder. In contrast, individuals with IED experience recurrent, spontaneous outbursts of anger that are not solely attributable to substance use

Summary

Intermittent Explosive Disorder (IED) is characterised by aggressive outbursts, either verbal or physical, which are often out of proportion to the provocation or stressor in their magnitude. The outbursts are distressing to people who are affected as well as those around them, can cause problems at work and in relationships, and can lead to adverse consequences. 

Considering the prevalence of IED and its causes, understanding the signs and symptoms of this disorder is important to understand and effectively identify individuals with IED. Though the symptoms might be intense and distressing, it is possible to manage them for improved physical and emotional safety and overall quality of life.