An investigation of the P3b evoked potential in psychopathy

Psychopathy is a developmental disorder involving both an emotional dysfunction
as well as antisocial behaviour. The treatment of psychopathy has been
relatively ineffective, and increased understanding of this disorder is needed.
The proposed study tries to contribute to this need. Psychopathic individuals
show abnormalities in the amplitude of an evoked potential called the P3b.
However, results have been mixed: several studies have found P3b decreases
during oddball tasks in psychopathic individuals relative to controls. In
contrast, one study did not find any differences in P3b amplitude, and one
study (Raine & Venables, 1988) even found enhanced P3b amplitudes in
psychopathic individuals relative to controls during a continuous performance
task (CPT). A recent meta-analysis (Gao & Raine, 2009) of P3 abnormalities in
antisocial and psychopathic individuals suggested that these inconsistent
results can be accounted for by differences in task complexity that either lead
to loss of attention due to boredom, or an increased focussed attention due to
sensation. However, this suggestion is supported by only one study and thus,
this study requires replication. We propose to use a similar task as the one
used by Raine and Venables (1988), more specifically, the AX-Continuous
Performance Task (AX-CPT), to measure both behavioural and electrophysiological
differences in performance between psychopathic and control individuals.
Furthermore, it has been suggested that P3 abnormalities may be indicative of
externalizing disorders in general, and not of psychopathy per se. Therefore we
will attempt to account for personality dimensions, drug abuse, and impulsivity
by controlling for these potential confounds. Results may contribute to an
increased understanding of some of the abnormalities in psychopathy. An
increased understanding of the abnormalities in psychopathy is needed for the
development of future (therapeutical) interventions.

We want to compare differences in height of focussed attention on an AX-CPT
between psychopathic and control individuals. To determine the height of
focussed attention, we will use measures of P3b, accuracy, and reaction times.
In addition, we want to control for externalizing disorder by controlling for
the variables personality pathology, impulsivity and history of drug abuse, in
addition to age and IQ.

cross-sectional design with a patient group and a healthy control group matched
on age, IQ, and sex.

Participation does not involve any risk for participants. Participants
coöperate in two sessions. In the first session, participants have to fill in
questionnaires and participate in a diagnostic interview. In the second
session, the participants will participate in an attention task during which
electroencephalogram (EEG) is recorded. Our understanding of underlying
psychophysiological deficiencies in psychopathy may be increased by this study.
A better understanding of deficiencies in psychopathy is needed for the
development of future (therapeutic) interventions.