Neurocognitive function in antisocial personality disorder - CiteSeer

18 Pages·2001·0.14 MB·English

PsychiatryResearch97(cid:14)2000.173]190
Neurocognitive function in antisocial personality
disorder
U
Wayne M. Dinn , Catherine L. Harris
DepartmentofPsychology,BostonUni¤ersity,64CummingtonStreet,Boston,MA02215,USA
Received20March2000;receivedinrevisedform6September2000;accepted22September2000
Abstract
Recent neuroimagingstudies andneuropsychologicaltest findingssupportthe contention that prefrontal dysfunc-
tion is associated with psychopathic personality traits and antisocial behavior. However, conflicting results have
arisen regardingperformance onmeasures offrontal executive function. Weadministered a neuropsychologicaltest
battery consisting of measures sensitive to frontal lobe dysfunction and a battery of personality questionnaires and
clinical scales sensitive to antisocial personality disorder (cid:14)APD. subjects presenting with prominent psychopathic
personalityfeatures andmatchedcontrolsubjects. Wealsomonitoredthe subjects’ electrodermal activityduringthe
presentation of emotionally charged stimuli. APD subjects showed greater neuropsychological deficits on measures
sensitivetoorbitofrontaldysfunctionincomparisontocontrolparticipants.Moreover,APDsubjectswereelectroder-
mally hyporesponsive to aversive stimuli relative to control group members. APD subjects did not demonstrate
performance deficits on classical tests of frontal executive function. Participants also underwent clinical assessment.
Asexpected,APDsubjects were less conscientious, self-reproaching, guilt-prone,andsocially anxious than matched
controlsubjects. Moreover,the scores indicatedthat APDsubjects weremoreventuresome anduninhibited relative
to control subjects. Contrary to expectations, APD subjects and community control subjects did not differ on a
self-report measure of sensitivity to specific phobic situations. Q 2000 Elsevier Science Ireland Ltd. All rights
reserved.
Keywords: Psychopathy;Frontallobe;Orbitofrontal;Dorsolateral]prefrontal;Neuropsychological;Electrodermal
UCorrespondingauthor.42WashingtonTerrace,Whitman,MA02382,USA.Tel.:q1-617-353-1362.
E-mailaddress:[email protected](cid:14)W.M.Dinn..
0165-1781r00r$-seefrontmatterQ2000ElsevierScienceIrelandLtd.Allrightsreserved.
PII: S0165-1781(cid:14)00.00224-9
174 W.M.Dinn,C.L.HarrisrPsychiatryResearch97(2000)173]190
1. Introduction function deficits are associated with antisocial
personality (cid:14)APD.. Morgan and Lilienfeld (cid:14)2000.
1.1. Prefrontaldysfunctionand psychopathy founda significant relationship between executive
function deficits and antisocial behavior.
Recent neuroimaging studies and neuropsycho- In response to Gorenstein’s study, Hare (cid:14)1984.
logical test findings support the contention that assigned inmates to low-, medium-, and high-psy-
prefrontal dysfunction (cid:14)particularly orbitofrontal. chopathy groups and administered the aforemen-
is associated with psychopathic personality traits tioned frontal executive function tasks. No sig-
and antisocial behavior (cid:14)Davidson et al., 2000; nificant group differences were observed. Hare
Raine et al., 1998, 2000; Lapierre et al., 1995.. was unable to replicate Gorenstein’s findings.
However,conflicting results havearisen regarding Sutker and Allain (cid:14)1987. also found that psycho-
the performance of psychopathic subjects on pathic subjects and control subjects performed
measures of frontal executive function. similarly on measures of concept formation, ab-
Several studies suggest that a select deficit in- straction, and planning. How can we account for
volvingthe orbitofrontal systemmayunderlie psy- these conflicting findings? One possibility is that
chopathy and antisocial behavior. Lapierre et al. the executive function deficits among psycho-
(cid:14)1995. found that incarcerated psychopathic sub- pathic subjects are associated with the presence
jects were significantly impaired on tasks con- of comorbidpsychiatric conditions,while the core
sidered sensitive to orbitofrontalrventrome- interpersonal and affective characteristics associ-
dial]prefrontal dysfunction including a visual ated with psychopathy(cid:14)e.g.,egocentricity, callous-
gorno]go discrimination task, Porteus Maze Q- ness, manipulativeness, guile, lack of empathy
scores (cid:14)i.e., rule-breaking errors., and an odor and remorse. may result from orbitofrontal dys-
identification task in comparison to matched con- function.
trolsubjects(cid:14)non-psychopathicinmates..Lapierre
et al. (cid:14)1995. also found that psychopathic subjects 1.2. Executi¤efunction and APD
did not display performance deficits on measures
sensitive to dorsolateral]prefrontal (cid:14)DLPF. and Several studies examining neurocognitive func-
posterorolandicfunction (cid:14)i.e.,the Wisconsin Card tion in psychopathy and APD reveal broadly
Sorting Test (cid:14)WCST. and the Mental Rotation frontal deficits,but if the prefrontal cortex can be
Task.. Moreover, Deckel et al. (cid:14)1996. reported fractionated into separate frontal subsystems,
that performanceontests assessing frontal execu- these may be differentially engaged in APD sub-
tive functioning (cid:14)e.g. the WCST, controlled oral types. One possibility is that APD subjects de-
word fluency test, and trail-making test. failed to monstrating corepsychopathictraits anda lack of
predict antisocial personality disorder classifica- foresight (cid:14)e.g.,difficultyanticipating negative con-
tions. These tasks are considered sensitive indica- sequences., planning, and goal-directed behavior
tors of DLPF dysfunction (cid:14)i.e., tasks which re- (cid:14)e.g., disorganized offending. will show greater
quire the employmentoforganizational strategies neuropsychological deficits on tasks considered
for efficient performance.. These findings suggest sensitive toorbitofrontal dysfunctionandonmea-
that a select orbitofrontal deficit may be associ- sures of frontal executive function. Specifically,
ated with psychopathy. core psychopathic personality characteristics may
However, Gorenstein (cid:14)1982. reported that psy- result from orbitofrontal dysfunction. The addi-
chopathic subjects demonstrated performance tional involvementofDLPFdysfunction maylead
deficits on tests of frontal executive function in- to antisocial behavior that combines core psycho-
cluding the WCST (cid:14)i.e., perseverative errors., pathic characteristics with poor planning and or-
Necker cube task, and a sequential matching me- ganization, and difficulty keeping in mind diverse
mory task. A recent meta-analytic review of 39 future consequences. Motivationforthis hypothe-
studies by Morgan and Lilienfeld (cid:14)2000. lends sis is that the DLPF cortex mediates executive
strong support to the contention that executive functions (cid:14)Smith and Jonides, 1999., while the
W.M.Dinn,C.L.HarrisrPsychiatryResearch97(2000)173]190 175
orbitofrontal cortex mediates sensitivity to dy- cation Test to investigate olfactory function. Ol-
namically changing reinforcement contingencies, factory identification tasks have been used to
and thus maybe particularly important for modu- assess the functional integrity of orbitofrontal
lating individuals’ response to the social world cortex. The orbitofrontal region plays a major
and other threat-laden situations. role in odor discrimination, and olfactory agnosia
has been reported in patients with damage to the
1.3.Isorbitofrontaldysfunctionthekeyto orbitofrontal aspect of the prefrontal cortex.
psychopathy? Jones-Gotman and Zatorre (cid:14)1988. reported that
patients with focal surgical brain lesions involving
Numerouscase reports describe the emergence orbitofrontal cortex were impaired on an odor
of psychopathic behavior following orbitofrontal identification task.
damage. Striking alterations in personality have The fact that orbitofrontal lesion patients un-
been well-documented. These patients demon- dergo a dramatic personality change (cid:14)alterations
strate social disinhibition, shallow affect, de- which strongly resemble primary psychopathy. is
creased empathy,and impulsive,antisocial behav- an intriguing line ofevidencewhich lends support
ior (cid:14)Blumer and Benson, 1975; Cummings, 1993; tothe contention that orbitofrontal dysfunction is
Damasio, 1994; Damasio and Van Hoesen, 1983; associated withpsychopathy.However,weare not
Grattan et al., 1994; Martzke et al., 1991; Meyers suggesting that an orbitofrontal lesion is an etio-
et al., 1992; Stuss et al., 1992.. Meyers et al. logic factor in psychopathy or APD. Rather, we
(cid:14)1992.reportedpost-operativebehavioralchanges support the hypothesis that orbitofrontal hypoac-
which ‘‘strongly resembled’’ APDin a 33-year-old tivity, in the absence of gross lesions, underlies
male with left orbitofrontal damage following primary psychopathy (cid:14)Lapierre et al., 1995.. Neu-
surgery for a pituitary tumor. It is noteworthy ropsychological test performance patterns and
that cognitive abilities are generally preserved in atypical electrodermal responses among psycho-
these patients, suggesting a highly selective dis- pathic subjects are consistent with the notionthat
ruption. orbitofrontal hypometabolism may underlie psy-
A significant bodyof research suggests that the chopathy.
orbitofrontal system plays a majorrole in regulat-
ing the individual’s emotional response to aver- 1.4. Psychophysiological testing, psychopathy, and
sive stimuli. Cummings (cid:14)1993. described the the orbitofrontalhypothesis
emergence of a disinhibition syndrome following
damage to the orbitofrontal region. Moreover,he Although atypical electrodermal responses is
noted that damage to subcortical structures (cid:14)e.g., associated with damage to non-frontal regions
caudate nucleus. is associated with the develop- (cid:14)Tranel and Damasio, 1994., converging lines of
ment of disinhibited behaviors similar to those evidence demonstrate that the orbitofrontal sys-
manifested by orbitofrontal lesion patients. tem contributes to the regulation of autonomic
Cummings (cid:14)1993. suggested that disruption of a nervous system (cid:14)ANS. activity including elec-
basal ganglia]thalamocortical circuit underlies trodermal activity and the rapid control of arte-
the characteristic changes. He concluded that rial pressure (cid:14)Damasio et al., 1990; Guyton, 1991;
these personality alterations constitute a circuit- Tranel and Damasio, 1994; Tranel et al., 1988..
specific neurobehavioral syndrome. Malloy et al. Tranel et al. (cid:14)1988. reported that human subjects
(cid:14)1993. also described an orbitomedial frontal be- with bilateral orbitofrontal lesions demonstrated
havioral syndrome distinguished by disinhibition, less reactive electrodermal responses during ex-
confabulation, anosmia, and Gorno]go deficits. posure to emotionally charged stimuli. Their
Interestingly, Lapierre et al. (cid:14)1995. reported that findings illustrate the importance of the or-
psychopathicsubjects wereless accurate atidenti- bitofrontal region in modulating autonomic re-
fying odors in comparison to matched control sponse to emotionally evocative events.
subjects. They used the Modular Smell Identifi- One possibility is that the reduced electroder-
176 W.M.Dinn,C.L.HarrisrPsychiatryResearch97(2000)173]190
malresponsivenessexhibitedbypsychopathicsub- 2. an assessment of autonomic reactivity among
jects reflects orbitofrontal hypofunction. On mul- APD subjects. We monitored the subjects’
tiple measures of ANSactivity, psychopathic indi- electrodermal activity duringthe presentation
viduals also exhibited reduced physiological reac- of emotionally charged stimuli;
tions to noxious stimuli. For example, psy- 3. an investigation of the relationship between
chopaths demonstrated diminished skin conduc- clinical presentation and neuropsychological
tance levels and were electrodermally hypo- test performance.
responsive to aversive stimuli (cid:14)Hare, 1978; Hare
et al., 1978; Hare and Craigen, 1974; House and
Milligan, 1976; Levander et al., 1979; Patrick et
al., 1994; Schalling et al., 1973; Tharp et al., 2. Methods
1980.. Researchers have suggested that the psy-
chopath’s diminished sensitivity to aversive sti-
Weadministered a neuropsychological test bat-
muli hinders the acquisition of avoidance respon-
tery consisting of measures sensitive to frontal
ses essential to socialization. Moreover,they con-
lobe dysfunction and a battery of personality
cluded that the psychopath’s profound lack of
questionnaires and clinical scales to antisocial
empathy may reflect an inability to generate ap- personality disorder (cid:14)APD. subjects and control
propriate autonomic responses to the pain or
subjects recruited from the general population.
distress experienced by another individual (cid:14)Hare,
We employed the community recruitment tech-
1978; Lykken, 1957.. Patrick et al. (cid:14)1994. pre- nique developed by Widom (cid:14)1977. to obtain the
sented findings which support the contention that APD sample. Widom (cid:14)1977. placed newspaper
psychopaths manifest a ‘‘deficit in physiological
advertisements seeking individuals exhibiting spe-
response during fear imagery, reflecting an im-
cific personality characteristics to participate in a
pairment of the normal associative processes by
research study. The advertisement described psy-
which symbolic stimuli (cid:14)in this case, language
chopathic personality traits in a non-pejorative
cues. prompt affect’’ (cid:14)p. 524.. This is consistent manner. Widom(cid:14)1977. reported that this method
with the somatic marker hypothesis of Damasio
was an effective means of recruiting non-institu-
(cid:14)1994.. Damasio and colleagues found that ven-
tionalized psychopathic subjects.
tromedial prefrontal lesion patients (cid:14)orbital and
Recruitment Advertisement
lower mesial frontal regions. were electroder-
mally hyporesponsive to emotionally charged sti-
‘‘Wanted charming, aggressive, carefree people who
muli.Ifelectrodermal hyporesponsivenessreflects
areimpulsivelyirresponsible, but aregoodathandling
orbitofrontal hypofunction, then APD subjects people and at looking after number one.’’ (cid:14)Widom,
exhibiting core psychopathic personality traits 1977,p.675..
should display reduced physiological reactions to
aversive stimuli. The APD group consisted of 12 male subjects
and their ages ranged from 19 to 34 years (cid:14)Ms
1.5. Research goals 27.8; SDs4.0.. The mean educational level of
the APD group was 13.9 years (cid:14)SDs1.7.. All
The principal objectives of this study were: APD subjects were right-handed as determined
by self-report. The APD subjects met the Diag-
1. an examination of the neurocognitive profiles nostic and Statistical Manual of Mental Disorders
of APD subjects presenting with prominent 4th ed.) (DSM-IV) diagnostic criteria for APD
psychopathic personality features. Work on (cid:14)AmericanPsychiatric Association,1994..Inaddi-
APD has also revealed broadly frontal defic- tion, we administered the Hare psychopathy
its, but if the prefrontal cortex can be fractio- checklist: screening version(cid:14)PCL:SV.(cid:14)Hartetal.,
nated into separate frontal subsystems, these 1995. to APD subjects. Upon completion of the
may be differentially engaged in APD; formaltesting session,weconductedasemi-struc-
W.M.Dinn,C.L.HarrisrPsychiatryResearch97(2000)173]190 177
tured interview with APD subjects designed to compensation(cid:14)$25persession..Written informed
elicit informationregardingeducationalandvoca- consent was obtained from all participants.
tional history, family background, prior psychoac- Approximately 65 individuals responded to the
tive substance use or abuse, and juvenile and APDrecruitment advertisements and30individu-
adult antisocial behavior. Eleven APD subjects als responded to control recruitment advertise-
exceeded the recommended cutoff score on the ments. Potential participants contacted our neu-
PCL:SV(cid:14)Gs18.(cid:14)Hart et al.,1995..Weincluded ropsychology lab in response to the newspaper
one additional subject who obtained a marginal advertisement. The lead author or a trained re-
score of 16 on the PCL:SV. The mean PCL:SV search assistant contacted the respondent and
score for the APD group was 18.5 (cid:14)SDs1.24.. It administered a brief screening interview (cid:14)based
is important to emphasize that APD and psy- on the PDQ-4 and the PCL:SV. over the tele-
chopathy may be discrete syndromes which often phone. Individuals were excluded if they were
coexist in the same individual. Moreover, the currently using psychotropic medications, re-
ported a history of electroconvulsive treatment,
studyofpsychopathicindividualswhopresentwith
or if they reported a history of traumatic head
or without a history of behavioral dyscontrol is
injury (cid:14)with loss of consciousness or cognitive
clearly warranted.Whilethis distinction mayhave
sequelae. or central nervous system pathology.
merit, we were unable to address it since all APD
Subsequent group assignment was based on
subjects in our study reported a long-standing
PDQ-4 and PCL:SV scores. APD subjects ex-
pattern of antisocial behavior and behavioral
ceeded the recommended symptom threshold on
dyscontrol dating back to late childhood or early
the PDQ-4(cid:14)APDsubscale.(cid:14)Hyler,1994..Inaddi-
adolescence, and displayed prominent psycho-
tion, 11 of 12 APD subjects exceeded the recom-
pathic characteristics. None of the APD subjects
mended cutoff scores on the psychopathy check-
or control participants were receiving psychoac-
list: screening version(cid:14)PCL:SV.(cid:14)Gs18.(cid:14)Hartet
tive drugs or met diagnostic criteria for substance
al., 1995.. The mean score on the APD subscale
abuse or dependence disorders at the time of
for the control group was 1.4, but was 6.6 for the
testing, although several APDsubjects reported a
APDsample. The mean score on the PCL:SV for
history of substance abuse. Individuals were ex-
the control group was 3.4, but was 18.5 for the
cluded if they were currently abusing alcohol or
APD sample. Clearly, APD subjects exceeded re-
other psychoactive substances. However,a history
commended cutoff scores on the PCL:SV. Con-
of substance abuse or dependence among APD
trol group scores on the PCL:SV were compara-
subjects did not constitute exclusion criteria. We
ble to published norms. Therefore, we are confi-
compared the performance patterns of APD sub-
dent that our control subjects were not psycho-
jects who met criteria (cid:14)lifetime. for alcohol or
pathic.
substance abuse to the neurocognitive profiles of
APD subjects who did not meet criteria for sub-
stance abuse or dependence. 2.1. Procedure
Ten male control subjects were recruited from
the general populationviaadvertisements seeking We administered neuropsychological measures
individuals interested in participating in research considered sensitive to orbitofrontal dysfunction
examining the neuropsychology of personality. including computerversions ofthe objectalterna-
Control subjects were matched to APD subjects tiontest(cid:14)Freedman,1990.,theStroopcolor]word
for age, educational level, handedness, and gen- test, and a visual gorno]go discrimination task
der. Their ages ranged from 21 to 41 (cid:14)Ms28.9; (cid:14)based onLapierre et al.,1995..All computerized
SDs6.9.. The mean educational level of the tasks were administered on a Macintosh IIci us-
control group was 13.9 years (cid:14)SDs1.7.. All con- ingPsyScope,experimental designsoftwaredevel-
trol subjects were right-handed, as determined by oped by Cohen et al. (cid:14)1993.. Reaction time and
self-report. All participants received financial voice onset latencies were collected using a mil-
178 W.M.Dinn,C.L.HarrisrPsychiatryResearch97(2000)173]190
lisecond timer that interfaces with the PsyScope ofSemanticWordNorms(cid:14)TogliaandBattig,1978.
software. In addition, we administered tests as- to categorize words (cid:14)see Appendix A..
sessing frontal executive functioning includingthe We also administered a battery of personality
controlled word fluency test (cid:14)FAS test. (cid:14)Good- questionnaires and clinical scales. Administered
glass and Kaplan, 1972. and a divergent thinking measures included Cattell’s 16PF questionnaire
task wbased on Guilford and Hoepfner (cid:14)1971.x. (cid:14)factors G, H, and O.; personality diagnostic
As noted previously, if electrodermal hypore- questionnaire (cid:14)PDQ-4; antisocial personality dis-
sponsiveness reflects orbitofrontal hypofunction, order. subscale (cid:14)Hyler, 1994., and a modified
then APD subjects exhibiting core psychopathic version of the fear survey schedule (cid:14)Wolpe and
personality traits should display reduced physio- Lang, 1964. consisting of three subscales. During
logical reactions to aversive stimuli. We tested the fear survey, participants were instructed to
this prediction by monitoringsubjects’ electroder- indicate the degree of avoidance behavior associ-
mal activity during the presentation of emotio- ated with specific situations or stimuli presented
nally charged stimuli. Subjects viewed 30 words on the computer screen because of fear or anxi-
possessingpositive,negative,orneutral emotional ety. Stimuli were classified in the following man-
connotations. Subjects rated the words (cid:14)displayed ner: (cid:14)1. social situations; (cid:14)2. specific phobic situa-
one at a time on the monitor. in terms of pleas- tions; and (cid:14)3. agoraphobic concerns. We also
antness (cid:14)1]7 scale. while the experimenter moni- administered subscales from the 16PF question-
naire (cid:14)factors G, H, and O. which reflect person-
tored the subjects’ electrodermal activity (cid:14)tonic
ality characteristics (cid:14)e.g.,lack of threat-sensitivity,
and phasic. with the Davicon C2A custom skin
guilt, conscientiousness, and behavioral inhibi-
conductance monitor (cid:14)NeuroDyne Medical Cor-
tion. associated with APD and psychopathy. We
poration, Cambridge, MA.. The resolution of the
anticipated that APD subjects would obtain low
Davicon C2A custom skin conductance system is
scores on factors O and G, reflecting a lack of
0.01 micromhos. Electrodes were attached to the
guilt and concern for social conventions, and
distal phalanges of the first and second fingers of
achieve high scores on factor H, reflecting social
the subject’s dominant hand. While conductive
disinhibition.
gel is used with Ag]AgCl electrodes, the contact
surface of the electrodes employed in our study
was gold, and gold electrodes do not require 2.2. Descriptionof neurocogniti¤etests and clinical
conductive paste. The combined effective surface scales
area of the sensors was 1 cm2. The subject’s skin
was not prepared. Data collection was divided
2.2.1. Object alternationtest
into 10-s intervals following the presentation of
Performance on the object alternation test is
each stimulus. Davicon psychophysiological as-
determined by number of trials required to in-
sessment software providedthe basepoint andthe
duce the solution. Subjects view two distinct sti-
maximum point during each interval and sub- mulus objects (cid:14)a red cup and a blue cup. on a
tracted the basepoint from the maximum score, computermonitor.Thecomputer‘hides’acoinin
yielding a measure ofSCRin micromhos.That is, one of the cups. The subjects are asked to de-
the software automatically calculated the ampli- termine which cup contains the coin. The coin
tude of the phasic response. We calculated the moves to the unoccupied cup following a correct
mean phasic response to each stimulus class (cid:14)i.e., response. Subjects receive immediate feedback
positive, negative, or neutral stimuli. for each from the computer regarding the accuracy of re-
subject. In addition, a research technician sponse following each choice. Participants reach
observed the subject during the word-rating task criterion when they correctly predict the coin
and noted if the participant moved during elec- location on 12 consecutive trials. The subjects’
trodermal monitoring. These trials were excluded score is the trial number of their last wrong
fromsubsequent analysis. Weusedthe Handbook response before the onset of their run of 12
W.M.Dinn,C.L.HarrisrPsychiatryResearch97(2000)173]190 179
correct trials. A low score indicates superior per- while the experimenter monitors subjects’ elec-
formance. The score of participants who never trodermal activity.
reach the solution is set to 50, the maximum
number of trials (cid:14)Freedman, 1990.. 2.2.5. Word fluency test (FAS test)
During the word fluency test (cid:14)FAS test., the
2.2.2. Stroop color]word test subject is asked to write down as many words as
During our computer version (cid:14)administered on possible that begin with a specific letter (cid:14)F, A, or
aMacintoshIIcicomputerusingtheexperimental S. during three 1-min trials (cid:14)Goodglass and Ka-
design software PsyScope., subjects are asked to plan, 1972..
read words as quickly as possible (cid:14)displayed one
at a time on the computer monitor. describing a 2.2.6. Di¤ergent thinking task
color. The ink color may be inconsistent with the This task is based on Guilford and Hoepfner
given word. During the first block (cid:14)non-conflict (cid:14)1971.. During the divergent thinking task, sub-
block., the subject is asked to read the word jects are asked to name as many different uses of
displayedonthe monitorandignorethe ink color anewspaperaspossibleduringa1-mintrial.They
(cid:14)40 trials.. During the second block (cid:14)conflict are providedwith the following example: one use
block., the participant is asked to identify the ink is rolling up the newspaper to swat a mosquito.
color(cid:14)40trials..Responselatencieswererecorded
using a voice-activated millisecond timer. Each 2.2.7. Personality diagnosticquestionnaire(PDQ-4)
trial ends when the subject responds verbally into (APD subscale)
a microphone. All participants completed both The PDQ-4 is a true]false questionnaire which
blocks. The dependent measure was response yieldssubscale scores reflecting DSM-IV diagnos-
time. tic criteria for axis-II disorders. Questions were
adapted from DSM-IV diagnostic criteria (cid:14)Hyler,
2.2.3. Gorno]go task 1994..
This test was based on Lapierre et al. (cid:14)1995..
Subjects press the space bar as quicklyas possible 2.2.8.Psychopathychecklist:screening¤ersion
when a 2=2-cm blue square appears (cid:14)against a (PCL:SV)
white background. on a computer monitor. Dur- The PCL:SV is designed to yield a total score
ingthefirstblock(cid:14)50trials.,onlybluesquares are and subscale scores reflecting two correlated fac-
displayed. During the second block (cid:14)50 trials., tors. Factor 1 reflects interpersonal and affective
subjects are instructed to respond when the blue characteristics associated with psychopathy such
square appearsandrefrain fromrespondingwhen as egocentricity and profound lack of empathy,
a 2=2-cm blue cross is displayed. During the while factor 2 reflects behavioral dyscontrol, im-
third block (cid:14)50 trials., subjects are instructed to pulsivity,andantisocialconduct(cid:14)Hartetal.,1995..
respond when the blue cross is displayed and
refrain fromrespondingwhenthesquareappears.
The blue square or blue cross appears at random 3. Results
locations across the computer screen. The inter-
stimulus interval is also randomizedwithintervals Since multiple comparisons were planned, we
of 100, 250, 400, 500, 750, 1000, and 2000 ms. controlled for type 1 errors with the Bonferroni
procedure. Thus, the alpha level was set to 0.003.
2.2.4. Assessment of autonomicacti¤ity
Subjects view30wordspossessing positive,neg- 3.1. Neuropsychologicaltesting
ative,orneutral emotionalconnotations.Thesub-
jects rate the words (cid:14)displayed one at a time on We conducted a multivariate analysis of vari-
the monitor. in terms of aversiveness (cid:14)1]7 scale. ance (cid:14)MANOVA..Significant MANOVAfindings
180 W.M.Dinn,C.L.HarrisrPsychiatryResearch97(2000)173]190
werefollowedupwithposthoccomparisonsusing the color-namingblocksofthe Stroopcolor]word
the Tukey test of significance. MANOVA indi- test (cid:14)see Table 1.. When required to inhibit a
cated that the APD group was impaired on tasks previously learned response pattern (cid:14)i.e., conflict
considered sensitive to orbitofrontal dysfunction blocks., APD subjects displayed greater reaction
relative to control subjects: Wilks’ Lambdas times in comparison to control subjects. Group
0.136; F s8.439; P-0.001. Subsequent uni- differences on the non-conflict blocks of the
9,12
variate analyses yielded significant group differ- Stroop (cid:14)wordnaming. (cid:14)Ps)0.35. and gorno]go
ences on the object alternation test (cid:14)F s (cid:14)block 1. (cid:14)P)0.11. tasks were not statistically
1,20
26.462, P-0.001., and conflict blocks of the significant. Contrary to expectation, group dif-
Stroop color]word test (cid:14)F s12.011, P-0.003 ferences on the conflict blocks of the gorno]go
1,20
and F s13.446, P-0.001.. APD subjects ex- task were not significant, although group differ-
1,20
hibited performance deficits on the object alter- ences on the third block of the gorno]go task
nation test and conflict blocks of the Stroop task approached significance (cid:14)P-0.06.. APD subjects
incomparisontocommunitycontrolsubjects.The didnot demonstrate performance deficits on clas-
mean number oftrials tosolvethe object alterna- sical tests of frontal executive function. Interest-
tion test was 11.8 (cid:14)SDs4.7. for the community ingly, the APD subjects generated significantly
control group, but was 33.9 (cid:14)SDs12.8. for the more responses on the divergent thinking task
APD group. than control participants (cid:14)F s14.051, P-
1,20
Relative to the community control group,APD 0.001.. APD subjects did produce fewer words on
subjects demonstrated slower reaction times on the word fluency test relative to control subjects,
Table1
Neuropsychologicaltestperformancea
Mean(cid:14)SD. Univariateanalysis
APD Controlsubjects F P
1,20
n 12 10
Age 27.8 (cid:14)4.0. 28.9 (cid:14)6.9. y0.202 0.658
Education 13.9 (cid:14)1.72. 13.9 (cid:14)1.74. 0.006 0.938
Handedness 100% Right 100% Right
OAT 33.9 (12.8) 11.8 (4.7) 26.462 -0.001
Stroopcolor]wordtest
StroopWord-c 479ms (cid:14)50. 505ms (cid:14)81. y0.843 0.369
StroopWord-i 521ms (cid:14)79. 549ms (cid:14)95. y0.606 0.445
StroopColor-c 948ms (223) 674ms (121) 12.011 -0.003
StroopColor-i 1214ms (334) 811ms (103) 13.446 -0.001
Gorno]gotask
Gorno]go}1 322ms (cid:14)61.5. 284ms (cid:14)38.9. 2.746 0.113
Gorno]go}2 495ms (cid:14)71.9. 468ms (cid:14)55.7. 0.943 0.345
Gorno]go}3 505ms (cid:14)56.3. 459ms (cid:14)45.9. 4.083 0.056
FASTest 38.0 (cid:14)5.6. 41.6 (cid:14)9.0. y1.294 0.268
DvT 9.5 (1.9) 6.8 (1.2) 14.051 0.001
SCR(micromhos) 0.02 (0.01) 0.14 (0.08) I24.333 -0.001
aNote: OATsobjectalternation test; StroopsStroopcolor]wordtest (cid:14)blocks 1and2swordnaming,blocks 3and4scolor
naming., cscongruent, isincongruent; Gorno]gosgorno go task (cid:14)blocks 1, 2, 3.; FASsControlled word fluency test (cid:14)FAS
test.;DvTsdivergentthinkingtask;mssmilliseconds;SCRsmeanamplitudeofskinconductanceresponse(cid:14)micromhos..
W.M.Dinn,C.L.HarrisrPsychiatryResearch97(2000)173]190 181
although this difference did not approach signifi- thePDQ-4(cid:14)F s67.663, P-0.001.,thePCL:SV
1,20
cance (cid:14)P)0.25.. (cid:14)F s631.315, P-0.001. and on factor H (cid:14)F
1,20 1,20
The mean amplitudes of skin conductance re- s18.782, P-0.001.. This clinical profile indi-
sponse (cid:14)SCR. to the three categories of words cates that APD subjects, as expected, were less
(cid:14)positive, neutral, and negative. were compared conscientious, self-reproaching, guilt-prone, and
across the subject groups.As expected, APDsub- socially anxious than matched control subjects.
jects were electrodermally hyporesponsive to Moreover,the scores indicated that APDsubjects
aversive stimuli relative to control group mem- were more venturesome and uninhibited relative
bers (cid:14)F sy24.333, P-0.001.. In addition, all
1,20 to control subjects. However, the scores of APD
participants,regardlessofgroupmembership,cat-
subjects on the specific phobic situations subscale
egorized words in the expected manner, demon-
did not differ significantly from the scores
strating that they were aware of the emotional achieved by control participants (cid:14)P)0.78. (cid:14)see
connotations of the stimuli.
Table2..Groupcomparisonrevealedamarginally
significant difference onthe agoraphobiasubscale
3.2. Clinical profile (cid:14)F sy6.364, P-0.02..
1,20
Five of 12 APD subjects reported a history of
substance abuse. To examine the impact of prior
MANOVA, followed by post hoc analyses, re-
substance abuse on neuropsychological test per-
vealed highly significant group differences on the
clinical scales and personality measures. As ex- formance,wecomparedthe performancepatterns
pected, APD subjects achieved significantly lower of APD subjects who met criteria (cid:14)lifetime. for
scores on factors O (cid:14)F sy18.768, P-0.001. alcohol or substance abuse to the neurocognitve
1,20
andG(cid:14)F sy12.814, P-0.001.fromthe16PF profiles of APD subjects who did not meet crite-
1,20
questionnaire, and on the social anxiety subscale ria for substance abuse or dependence. The clini-
(cid:14)F sy34.246, P-0.001. in comparison to cal and neurocognitive profiles of these groups
1,20
control subjects. In addition, they displayed sig- were remarkably similar. Groups did not differ
nificantly higher scores on the APD subscale of significantly on the object alternation test (cid:14)P)
Table2
Personalityandclinicalfindingsa
ClinicalCharacteristics Mean(cid:14)SD. Univariateanalysis
APD Controlsubjects F P
1,20
N 12 10
16PFSubscales
FactorG 6.4 (3.7) 11.3 (2.4) I12.814 -0.001
FactorH 20.5 (2.7) 13.3 (4.9) 18.782 -0.001
FactorO 7.8 (2.8) 12.6 (2.3) I18.768 -0.001
FearSur¤eySubscales
Agoraphobia 1.9 (cid:14)3.2. 5.8 (cid:14)4.0. y6.364 -0.02
Socialanxiety 3.9 (3.3) 15.5 (5.8) I34.246 -0.001
Specificphobia 13.2 (cid:14)8.8. 14.1 (cid:14)4.6. y0.075 0.787
APD(PDQ) 6.6 (1.78) 1.4 (0.96) 67.663 -0.001
PCL:SV 18.5 (1.2) 3.4 (1.5) 631.315 -0.001
aNote:16PFQuestionnaire } factors G,H,andO; Fear survey schedule } agoraphobiasubscale; specific phobiasubscale;
social anxiety subscale.; Personality diagnostic questionnaire (cid:14)PDQ-4.; APDsantisocial personality disorder subscale (cid:14)PDQ-4.;
Psychopathychecklist: screeningversion(cid:14)PCL:SV..
182 W.M.Dinn,C.L.HarrisrPsychiatryResearch97(2000)173]190
0.45., Stroop color]word test (cid:14)all Ps)0.15., trial. Thecoinshifted tothe unoccupiedcupafter
gorno]gotask (cid:14)all Ps)0.10.,verbal fluency task the correct response. The subject continued to
(cid:14)P)0.12.,anddivergentthinking task (cid:14)P)0.15.. choose the cup which originally contained the
In addition, groups did not exhibit significantly coin andmade49consecutive incorrect responses
different patterns of autonomic reactivity (cid:14)P) (cid:14)despite the fact that the research technician
0.25.. pointed out that he was free to choose the other
cup..
APD subjects did not demonstrate perfor-
4. Discussion mance deficits on classical tests of frontal execu-
tive function. Our findings are consistent with the
4.1. Neurocogniti¤etest findings contention that a highly select deficit involving
the orbitofrontal system is associated with psy-
APD subjects showed greater neuropsychologi- chopathy and APD.
cal deficits on measures sensitive to orbitofrontal Contrary to prediction, group differences on
dysfunction in comparisonto control participants. the gorno]go Task were not statistically signifi-
Performance deficits on the object alternation cant. We anticipated that APD subjects would
test may reflect an inability to effectively process exhibit performance deficits (cid:14)e.g., reaction time
feedback information regarding reward and pun- slowing.onthe gorno]goTask.Thisfindingdoes
ishment (cid:14)i.e., the inability to successfully employ not supportour central hypothesis. Unexpectedly,
punishment cues to guide behavior.. Rolls (cid:14)1995. APD subjects performed significantly better than
suggested that the orbitofrontal region de- control subjects on the divergent thinking task.
termines the reinforcing value of stimuli. Toourknowledge,thedivergentthinkingtaskhas
In our prior unpublished work, performance never been administered to APD or psychopathic
deficits on the gorno]go and Stroop tasks (cid:14)con- subjects. However, it is interesting to note that
flict blocks. correlated strongly with object alter- several studies found that individuals psychomet-
nation test performance, suggesting that the or- rically defined as extraverted, or exhibiting low
bitofrontal system is involved in the inhibition of levels of anxiety, obtained significantly higher
a dominant or prepotent response pattern, which scores on divergent thinking tasks.
is consistent with its role in modifyingbehavior in
responsetochanging contingencies. In addition,a 4.2. Do the neuropsychologicalmeasures employed
number of APD subjects were unable to identify possess localizing¤alue?
the correct alternation pattern. The score of par-
ticipants who never reached the solution was set Patients with prefrontal damage perform simi-
at 50, the maximum number of trials. Interest- larly to control subjects on measures of general
ingly, several of these subjects employed ‘super- cognitive ability (cid:14)i.e., standard intelligence test
stitious’ response strategies. For example, one scores are typically in the normal range. and on
APDsubjectstatedthat‘everythinggoesinthrees’ verbal and non-verbal memory tasks (cid:14)e.g., paired
and he wouldmake three perseverative responses associate learning.. However, careful neuropsy-
before shifting to the alternate choice (cid:14)i.e., the chologicalexamination willrevealsubtle cognitive
correct location.. We should note that we did not deficits.Researchers havecometoappreciatethat
screen APD subjects for schizotypal personality the prefrontal region is not a unitary structure;
traits. It would be interesting to determine if the rather, it is fractionable into anatomically and
presence of schizotypal features among APD or functionally distinct subsystems. Converging lines
psychopathic subjects is associated with perfor- of evidence suggest that dorsolateral-prefrontal
mance deficits on the object alternation test. cortex mediates executive functions (cid:14)Smith and
Moreover, several APD subjects exhibited ex- Jonides, 1999., while orbitofrontal cortex modu-
treme perseverative behavior. For example, one lates sensitivity to reinforcement contingencies
APD subject made a correct choice on the initial (cid:14)Rolls, 1995..