468 Disruptive, Impulse-Control, and Conduct Disorders
Genetic and physiological. First-degree relatives of individuals with intermittent ex-
plosive disorder are at increase d risk for intermittent explos ive disorder, and twin studies
have demonstrated a substantial geneti c influence for impulsive aggression. 
Research provides neurobiolo gical support for the presence of serotonergic abnormal-
ities, globally and in the brain, specifically in areas of the limbic sy stem (anterior cingulate)
and orbitofrontal cortex in individuals with  intermittent explos ive disorder. Amygdala
responses to anger stimuli, during function al magnetic resonance imaging scanning, are
greater in individuals with intermittent expl osive disorder compared with healthy indi-
viduals.
Culture-Related Diagnostic Issues 
The lower prevalence of intermittent explosive disorder in some regions (Asia, Middle
East) or countries (Romania, Nigeria), compared  with the United States, suggests that in-
formation about recurrent, prob lematic, impulsive aggressive behaviors either is not elic-
ited on questioning or is less likely to be present, because of cultural factors.
Gender-Related Diagnostic Issues
In some studies the prevalence of intermittent explosive diso rder is greater in males than
in females (odds ratio = 1.4–2.3); other st udies have found no gender difference. 
Functional Consequences of 
Intermittent Explosive Disorder
Social (e.g., loss of friends, relatives, marita l instability), occupational (e.g., demotion, loss
of employment), financial (e.g., due to value of objects destroyed), and legal (e.g., civil
suits as a result of aggressive behavior against person or prop erty; criminal charges for as-
sault) problems often develop as a result of intermit tent explosive disorder. 
Differential Diagnosis