Background
This comparative and comprehensive study builds on a previous study comparing the P300 wave of impulsively violent delinquents and a non-impulsive non-delinquent group. The purpose was to investigate changes in P300 cognitive evoked potentials, especially the amplitude and latency at the Pz electrode site.
Material and Method
The P300 parameters of perpetrators of various types of criminal offences and those of a control group matched for age, gender, and educational status were compared (N=80). There were 20 subjects with impulsively aggressive delinquent behavior. The observed parameters were compared with the neuropsychophysiological correlates of a group of 20 subjects with deliberately (i.e. non-impulsive) violent behavior, a group of 20 delinquents sentenced for property crimes (theft), and 20 non-delinquent non-impulsive nonviolent persons. To differentiate these groups, Eysenck's IVE questionnaire and a structured interview according to DSM IV criteria conducted by a certified forensic psychiatrist were used.
Results
The results showed a significantly lower P300 wave amplitude in the impulsively aggressive individuals than in the other groups. No significant differences were found in terms of latency. The results confirm the results of previous studies.
Conclusions
The results suggest the possibility of a neuropsychophysiological correlate of impulsively aggressive individuals behaving in a socially dangerous way. This opens a discussion on the subject of expert evaluation of criminal acts within the context of "uncontrolled affect".

Keywords: Crime, Event-Related Potentials, P300 - physiology, Confidence Intervals, Analysis of Variance