474 Disruptive, Impulse-Control, and Conduct Disorders
Genetic and physiological. Conduct disorder is influenced by both genetic and envi-
ronmental factors. The risk is increased in child ren with a biological or adoptive parent or
a sibling with conduct disorder. The disorder also appears to be more common in children
of biological parents with severe alcohol us e disorder, depressive and bipolar disorders, or
schizophrenia or biological parents who have  a history of ADHD or conduct disorder.
Family history particularly characterizes in dividuals with the childhood-onset subtype of
conduct disorder. Slower resting heart rate has been reliably noted in individuals with
conduct disorder compared with those without the disorder, and this marker is not char-
acteristic of any other mental  disorder. Reduced autonomic fe ar conditioning, particularly
low skin conductance, is also well documented. However, these psychophysiological find-
ings are not diagnostic of the disorder. Structural and functional differences in brain areas
associated with affect regulation and affect processing, particularly frontotemporal-limbic
connections involving the brain’s ventral pref rontal cortex and amygdala, have been con-
sistently noted in individuals with conduct d isorder compared with those without the dis-
order. However, neuroimaging findings are not diagnostic of the disorder.
Course modifiers. Persistence is more likely for indi viduals with behaviors that meet
criteria for the childhood-onset subtype and qualify for the specifier “with limited pro-
social emotions”. The risk that conduct disorder will persist is also increased by co-occurring
ADHD and by substance abuse. 
Culture-Related Diagnostic Issues
Conduct disorder diagnosis may at times be potentially misapplied to individuals in set-
tings where patterns of disruptive behavior are viewed as near-normative (e.g., in very