Intermittent explosive disorder
Encyclopedia
Intermittent explosive disorder (abbreviated IED) is a behavioral disorder characterized by extreme expressions of anger
, often to the point of violence, that are disproportionate to the situation at hand. It is currently categorized in the Diagnostic and Statistical Manual of Mental Disorders
as an impulse control disorder
. IED belongs to the larger family of Axis I impulse control disorders listed in the DSM-IV-TR, along with kleptomania
, pyromania
, pathological gambling, and others. Impulsive aggression is unpremeditated, and is defined by a disproportionate reaction to any provocation, real or perceived. Some individuals have reported affective changes prior to an outburst (e.g., tension
, mood
changes, energy changes, etc.).
A 2006 study suggests that the disorder is considerably more prevalent than previously thought. In a study of almost 10,000 individuals 18 years or older, lifetime episodes were reported at 7.3%, while 12-month occurrences were reported at 3.9%. This suggests a mean lifetime occurrence of 43 instances, with an average of $1359 in property damage.
A 2005 study conducted in the U.S. State of Rhode Island found the prevalence to be 6.3% (SE, +/- 0.7%) for lifetime DSM-IV IED in a study of 1300 patients under psychiatric evaluation. Prevalence is higher in men than in women. The disorder itself is not easily characterized and often exhibits comorbidity with other mood disorders, particularly bipolar disorder
. Individuals diagnosed with IED report their outbursts were brief (lasting less than an hour), with a variety of bodily symptoms (sweating, chest tightness, twitching, palpitation
s) reported by a third of one sample. The violent acts were frequently reported accompanied by a sensation of relief, and in some cases, pleasure, but accompanied by remorse
after the fact.
, borderline personality disorder
, attention deficit/hyperactivity disorder, etc.) have been ruled out. Furthermore, the acts of aggression must not be due to a general medical condition, e.g., a head injury, Alzheimer’s disease, etc., or due to substance abuse
or medication. Diagnosis is made using a psychiatric interview to affective and behavioral symptoms to the criteria listed in the DSM-IV.
The DSM IV-TR is very specific in its definition of Intermittent Explosive Disorder which is defined, essentially, by exclusion of other conditions. The diagnosis requires:
Treatment is achieved through both cognitive behavioral therapy and psychotropic medication regimens, though the pharmaceutical options have shown limited success. Therapy aids in helping the patient recognize the impulses in hopes of achieving a level of awareness and control of the outbursts, along with treating the emotional stress that accompanies these episodes. Multiple drug regimens are frequently indicated for IED patients. Cognitive Relaxation and Coping Skills Therapy (CRCST) has shown preliminary success in both group and individual settings compared to waitlist control groups. This therapy focuses consists of 12 sessions, the first three focus relaxation training, then cognitive restructuring, then exposure therapy. The final sessions focus on resisting aggressive impulses and other preventative measures.
Tricyclic antidepressant
s and selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine
, fluvoxamine
, and sertraline
appear to alleviate some pathopsychological symptoms; the reasons for such will be explained further in the subsequent section. GABAergic mood stabilizer
s and anticonvulsive drugs such as gabapentin
, lithium
, carbamazepine
, and divalproex seem to aid in controlling the incidence of outbursts. Anxiolytics help alleviate tension and may help reduce explosive outbursts by increasing the provocative stimulus tolerance threshold, and are especially indicated in patients with comorbid obsessive-compulsive or other anxiety disorders.
Impulsive behavior, and especially impulsive violence predisposition has been correlated to a low brain serotonin
turnover rate, indicated by a low concentration of 5-Hydroxyindoleacetic acid
(5-HIAA) in the cerebrospinal fluid
(CSF). This substrate
appears to act on the suprachiasmatic nucleus
in the hypothalamus
, which is the target for serotonergic output from the dorsal and median raphe nuclei
playing a role in maintaining the circadian rhythm
and regulation of blood sugar
. A tendency towards low 5-HIAA may be hereditary
. A putative hereditary component to low CSF 5-HIAA and concordantly possibly to impulsive violence has been proposed. Other traits that correlate
with IED are low vagal tone and increased insulin
secretion. A suggested explanation for IED is a polymorphism
of the gene
for tryptophan hydroxylase
, which produces a serotonin precursor
; this genotype
is found more commonly in individuals with impulsive behavior.
IED may also be associated with lesions in the prefrontal cortex
, with damage to these areas, including the amygdala
, increasing the incidence of impulsive and aggressive behavior and the inability to predict the outcomes of an individual's own actions. Lesions in these areas are also associated with improper blood sugar control, leading to decreased brain function in these areas, which are associated with planning and decision making. A national sample in the United States
estimated that 16 million Americans may fit the criteria for IED.
Anger
Anger is an automatic response to ill treatment. It is the way a person indicates he or she will not tolerate certain types of behaviour. It is a feedback mechanism in which an unpleasant stimulus is met with an unpleasant response....
, often to the point of violence, that are disproportionate to the situation at hand. It is currently categorized in the Diagnostic and Statistical Manual of Mental Disorders
Diagnostic and Statistical Manual of Mental Disorders
The Diagnostic and Statistical Manual of Mental Disorders is published by the American Psychiatric Association and provides a common language and standard criteria for the classification of mental disorders...
as an impulse control disorder
Impulse control disorder
Impulse control disorder is a set of psychiatric disorders including intermittent explosive disorder, kleptomania, pathological gambling, pyromania , and three body-focused repetitive or compulsive behaviors of trichotillomania , onychophagia and dermatillomania...
. IED belongs to the larger family of Axis I impulse control disorders listed in the DSM-IV-TR, along with kleptomania
Kleptomania
Kleptomania is an irresistible urge to steal items of trivial value. People with this disorder are compelled to steal things, generally, but not limited to, objects of little or no significant value, such as pens, paper clips, paper and tape...
, pyromania
Pyromania
Pyromania in more extreme circumstances can be an impulse control disorder to deliberately start fires to relieve tension or for gratification or relief. The term pyromania comes from the Greek word πῦρ . Pyromania and pyromaniacs are distinct from arson, the pursuit of personal, monetary or...
, pathological gambling, and others. Impulsive aggression is unpremeditated, and is defined by a disproportionate reaction to any provocation, real or perceived. Some individuals have reported affective changes prior to an outburst (e.g., tension
Stress (biology)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...
, mood
Mood (psychology)
A mood is a relatively long lasting emotional state. Moods differ from emotions in that they are less specific, less intense, and less likely to be triggered by a particular stimulus or event....
changes, energy changes, etc.).
A 2006 study suggests that the disorder is considerably more prevalent than previously thought. In a study of almost 10,000 individuals 18 years or older, lifetime episodes were reported at 7.3%, while 12-month occurrences were reported at 3.9%. This suggests a mean lifetime occurrence of 43 instances, with an average of $1359 in property damage.
A 2005 study conducted in the U.S. State of Rhode Island found the prevalence to be 6.3% (SE, +/- 0.7%) for lifetime DSM-IV IED in a study of 1300 patients under psychiatric evaluation. Prevalence is higher in men than in women. The disorder itself is not easily characterized and often exhibits comorbidity with other mood disorders, particularly bipolar disorder
Bipolar disorder
Bipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
. Individuals diagnosed with IED report their outbursts were brief (lasting less than an hour), with a variety of bodily symptoms (sweating, chest tightness, twitching, palpitation
Palpitation
A palpitation is an abnormality of heartbeat that causes a conscious awareness of its beating, whether it is too slow, too fast, irregular, or at its normal frequency. The word may also refer to this sensation itself...
s) reported by a third of one sample. The violent acts were frequently reported accompanied by a sensation of relief, and in some cases, pleasure, but accompanied by remorse
Remorse
Remorse is an emotional expression of personal regret felt by a person after he or she has committed an act which they deem to be shameful, hurtful, or violent. Remorse is closely allied to guilt and self-directed resentment...
after the fact.
Diagnosis
The DSM-IV criteria for IED include: the occurrence of discrete episodes of failure to resist aggressive impulses that result in violent assault or destruction of property, the degree of aggressiveness expressed during an episode is grossly disproportionate to provocation or precipitating psychosocial stressor, and, as previously stated, diagnosis is made when other mental disorders that may cause violent outbursts (e.g., antisocial personality disorderAntisocial personality disorder
Antisocial personality disorder is described by the American Psychiatric Association's Diagnostic and Statistical Manual, fourth edition , as an Axis II personality disorder characterized by "...a pervasive pattern of disregard for, and violation of, the rights of others that begins in childhood...
, borderline personality disorder
Borderline personality disorder
Borderline personality disorder is a personality disorder described as a prolonged disturbance of personality function in a person , characterized by depth and variability of moods.The disorder typically involves unusual levels of instability in mood; black and white thinking, or splitting; the...
, attention deficit/hyperactivity disorder, etc.) have been ruled out. Furthermore, the acts of aggression must not be due to a general medical condition, e.g., a head injury, Alzheimer’s disease, etc., or due to substance abuse
Substance abuse
A substance-related disorder is an umbrella term used to describe several different conditions associated with several different substances .A substance related disorder is a condition in which an individual uses or abuses a...
or medication. Diagnosis is made using a psychiatric interview to affective and behavioral symptoms to the criteria listed in the DSM-IV.
The DSM IV-TR is very specific in its definition of Intermittent Explosive Disorder which is defined, essentially, by exclusion of other conditions. The diagnosis requires:
- several episodes of impulsive behavior that result in serious damage to either persons or property, wherein
- the degree of the aggressiveness is grossly disproportionate to the circumstances or provocation, and
- the episodic violence cannot be better accounted for by another mental or physical medical condition.
Treatment
Treatment is achieved through both cognitive behavioral therapy and psychotropic medication regimens, though the pharmaceutical options have shown limited success. Therapy aids in helping the patient recognize the impulses in hopes of achieving a level of awareness and control of the outbursts, along with treating the emotional stress that accompanies these episodes. Multiple drug regimens are frequently indicated for IED patients. Cognitive Relaxation and Coping Skills Therapy (CRCST) has shown preliminary success in both group and individual settings compared to waitlist control groups. This therapy focuses consists of 12 sessions, the first three focus relaxation training, then cognitive restructuring, then exposure therapy. The final sessions focus on resisting aggressive impulses and other preventative measures.
Tricyclic antidepressant
Tricyclic antidepressant
Tricyclic antidepressants are heterocyclic chemical compounds used primarily as antidepressants. The TCAs were first discovered in the early 1950s and were subsequently introduced later in the decade; they are named after their chemical structure, which contains three rings of atoms...
s and selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine
Fluoxetine
Fluoxetine is an antidepressant of the selective serotonin reuptake inhibitor class. It is manufactured and marketed by Eli Lilly and Company...
, fluvoxamine
Fluvoxamine
Fluvoxamine is an antidepressant which functions as a selective serotonin reuptake inhibitor . Fluvoxamine was first approved by the U.S. Food and Drug Administration in 1993 for the treatment of obsessive compulsive disorder . Fluvoxamine CR is approved to treat social anxiety disorder...
, and sertraline
Sertraline
Sertraline hydrochloride is an antidepressant of the selective serotonin reuptake inhibitor class. It was introduced to the market by Pfizer in 1991. Sertraline is primarily used to treat major depression in adult outpatients as well as obsessive–compulsive, panic, and social anxiety disorders in...
appear to alleviate some pathopsychological symptoms; the reasons for such will be explained further in the subsequent section. GABAergic mood stabilizer
Mood stabilizer
A mood stabilizer is a psychiatric medication used to treat mood disorders characterized by intense and sustained mood shifts, typically bipolar disorder.-Uses:...
s and anticonvulsive drugs such as gabapentin
Gabapentin
Gabapentin is a pharmaceutical drug, specifically a GABA analogue. It was originally developed for the treatment of epilepsy, and currently is also used to relieve neuropathic pain...
, lithium
Lithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
, carbamazepine
Carbamazepine
Carbamazepine is an anticonvulsant and mood-stabilizing drug used primarily in the treatment of epilepsy and bipolar disorder, as well as trigeminal neuralgia...
, and divalproex seem to aid in controlling the incidence of outbursts. Anxiolytics help alleviate tension and may help reduce explosive outbursts by increasing the provocative stimulus tolerance threshold, and are especially indicated in patients with comorbid obsessive-compulsive or other anxiety disorders.
Impulsive behavior, and especially impulsive violence predisposition has been correlated to a low brain serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...
turnover rate, indicated by a low concentration of 5-Hydroxyindoleacetic acid
5-Hydroxyindoleacetic acid
5-Hydroxyindoleacetic acid is the main metabolite of serotonin in the human body. In chemical analysis of urine samples, 5-HIAA is used to determine the body's levels of serotonin.- Clinical significance :...
(5-HIAA) in the cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
(CSF). This substrate
Substrate (biochemistry)
In biochemistry, a substrate is a molecule upon which an enzyme acts. Enzymes catalyze chemical reactions involving the substrate. In the case of a single substrate, the substrate binds with the enzyme active site, and an enzyme-substrate complex is formed. The substrate is transformed into one or...
appears to act on the suprachiasmatic nucleus
Suprachiasmatic nucleus
The suprachiasmatic nucleus or nuclei, abbreviated SCN, is a tiny region on the brain's midline, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms...
in the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
, which is the target for serotonergic output from the dorsal and median raphe nuclei
Raphe nuclei
The raphe nuclei are a moderate-size cluster of nuclei found in the brain stem. Their main function is to release serotonin to the rest of the brain...
playing a role in maintaining the circadian rhythm
Circadian rhythm
A circadian rhythm, popularly referred to as body clock, is an endogenously driven , roughly 24-hour cycle in biochemical, physiological, or behavioural processes. Circadian rhythms have been widely observed in plants, animals, fungi and cyanobacteria...
and regulation of blood sugar
Blood sugar
The blood sugar concentration or blood glucose level is the amount of glucose present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM , or 64.8 and 104.4 mg/dL...
. A tendency towards low 5-HIAA may be hereditary
Heredity
Heredity is the passing of traits to offspring . This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve...
. A putative hereditary component to low CSF 5-HIAA and concordantly possibly to impulsive violence has been proposed. Other traits that correlate
Correlation
In statistics, dependence refers to any statistical relationship between two random variables or two sets of data. Correlation refers to any of a broad class of statistical relationships involving dependence....
with IED are low vagal tone and increased insulin
Insulin
Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....
secretion. A suggested explanation for IED is a polymorphism
Polymorphism (biology)
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
of the gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
for tryptophan hydroxylase
Tryptophan hydroxylase
Tryptophan hydroxylase is an enzyme involved in the synthesis of the neurotransmitter serotonin. TPH catalyzes the following chemical reactionIt employs one cofactor, iron.- Function :...
, which produces a serotonin precursor
Precursor (chemistry)
In chemistry, a precursor is a compound that participates in the chemical reaction that produces another compound. In biochemistry, the term "precursor" is used more specifically to refer to a chemical compound preceding another in a metabolic pathway....
; this genotype
Genotype
The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...
is found more commonly in individuals with impulsive behavior.
IED may also be associated with lesions in the prefrontal cortex
Prefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...
, with damage to these areas, including the amygdala
Amygdala
The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
, increasing the incidence of impulsive and aggressive behavior and the inability to predict the outcomes of an individual's own actions. Lesions in these areas are also associated with improper blood sugar control, leading to decreased brain function in these areas, which are associated with planning and decision making. A national sample in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
estimated that 16 million Americans may fit the criteria for IED.