596 CHAPTER 13
require processing emotional pictures and words (Intrator et al., 1997; Kiehl et al.,
2001). Moreover, these patients exhibit defi cits on tasks that rely on the frontal
lobes, such as those requiring planning or discovering that a rule has been changed
(Dolan & Park, 2002). Such defi cits probably contribute to their problems in in-
hibiting and planning behavior, and may also suggest that these people would have
diffi culty learning emotion-related information.Neural Communication Antisocial personality disorder has been linked to genes that
regulate dopamine production (Prichard et al., 2007) and also to genes that regulate
serotonin (Lyons-Ruth et al., 2007). In fact, the dopamine and serotonin systems
may not interact in normal ways in these patients. In one study, a novel drug that
affects the balance of these systems (in complex ways) improved a range of psy-
chological symptoms in patients with borderline personality disorder (Nickel et al.,
2006)—such a study has yet to be conducted to examine antisocial personality dis-
order, but researchers speculate that the results would tell the same story.
Abnormal brain functioning may refl ect or contribute to underlying differences
in temperament. For instance, men diagnosed with antisocial personality disorder in
adulthood were, at 3 years old, identifi ed as distractible, impulsive, and restless (Caspi
et al., 1996); these same qualities are observed in children with conduct disorder,
which is to be expected, given the diagnostic criteria for antisocial personality disor-
der. However, these qualities are also evident in attention-defi cit/hyperactivity disorder,
which is not a precursor to the personality disorder (Satterfi eld, 1987).Genetics As just noted, genes that affect dopamine and serotonin have been linked
to this disorder, and these genes may infl uence temperament; thus, it is interesting
that people with antisocial personality disorder consistently exhibit a number of
specifi c temperament dimensions. One such dimension is high reward dependence—
being highly motivated by the possibility of reward (Gray, 1987). Another is low
harm avoidance, which can be thought of as low anxiety or as not being strongly
motivated by the threat of punishment (Cloninger, 1987; Cloninger, Svrakic, &
Przybeck, 1993; Gray, 1987; Lykken, 1995). A third temperament dimension shared
by these people is low persistence—low frustration tolerance—which often leads to
impulsive behavior and a tendency to take shortcuts.
And, in fact, researchers have reported evidence that genes contribute to these dis-
tinctive temperament dimensions (Zuckerman, 1991). Although few genetic studies
focus on antisocial personality disorder specifi cally, what studies there are generally
reveal that genetic factors bias a person to develop conduct disorder and criminal-
ity (Cadoret et al., 1995; Nigg & Goldsmith, 1994; Slutske et al., 1997). Adoption
studies have found that the environment in which a child is raised infl uences the risk
of criminal behavior or antisocial personality disorder only if the child is biologi-
cally vulnerable, as shown in Table 13.13. When a child’s biological parents were not
criminals, the child’s later criminal behavior was unaffected by environmental infl u-
ences, such as the number of foster placements before adoption or the adoptive par-
ents’ criminality (Caspi et al., 2002; Mednick, Gabrielli, & Hutchings, 1984).Table 13.13 • Percentage of Children Who Later Committed Crimes: The
Role of Biology and Family Environment in CriminalityExposure to Environmental Forces
Associated with CriminalityBiological Parents’ CriminalityHigh LowHigh 40.0% 6.7%Low 12.1% 2.9%Note: Environmental forces associated with criminality include variables such as the number of foster
placements before adoption and the adoptive father’s socioeconomic status.
Source: Brock et al., 1996. For more information see the Permissions section.P SN