Neurobiological factors in aggressive and antisocial juveniles. A prospective longitudinal research on the predictive value of neurobiological factors on the development and course of aggressive and antisocial behavior.

Antisocial behavior by children is a major public health problem. Individual
functioning of these children is often poor and they are at risk for a series
of negative outcomes in adulthood, in particular children who showed the first
signs of antisocial behavior at young age. Risk factors which are important in
explaining antisocial behavior can be divided in psychosocial and biological
factors. It is important to acquire a better understanding of the development
and persistence of antisocial behavior, to ultimately result in earlier and
more effective interventions.

This follow-up study aims to investigate whether neurbiological factors (heart
rate, cortisol, testosterone) can predict the persistence of antisocial
behavior in boys who attended a delinquency diversion program four years
earlier, at the age of 12-14 years. The coherence between the development of
neurobiological factors and the course of behavior problems over four years of
time will be examined in addition.

It concerns a prospective longitudinal study design.
In order to obtain data of crime and recidivism, the *Herkenningssysteem* (HKS,
recognition system) of the police will be used, next to the *Justitie
Documentatie Systeem* (JDS, judicial documentation system).
Sociodemographic, psychosocial and behavioral variables will be measured by
means of a structured psychiatric interview (DISC) and self report
questionnaires (both obtained from the boys and their parents).
Neurobiological parameters include salivary cortisol, testosterone and heart
rate. Cortisol and heart rate will be measured during resting and stressful
conditions. A standardized psychosocial stress test will be used; a Public
Speaking Task with video recording.

The prevalence of disruptive behavior disorders, psychosocial problems and
various types of aggression will be assessed by using a standardized
psychiatric interview (NIMH-DISC IV) and various self report questionnaires,
both administered from the participants as well as their parent(s).
The neurobiological factors that will be measured include salivary cortisol and
testosterone, and heart rate. Cortisol and heart rate will be obtained during
resting and stressful conditions. For this purpose, a standardized psychosocial
stress test will be used, this is a Public Speaking Task with video recording.
It is guaranteed that any experienced stress will be stopped immediately after
the test.
On a weekday, three saliva samples will be collected, immediately after
awakening and after 30 and 60 minutes. The participant chews on a cotton swab
for this purpose. This is a non-invasive method which can be done at home by
the participant himself.
A few days or weeks after the last mentioned day the participant comes to the
institute for the mentioned psychosocial test. Seven saliva samples will be
obtained during this two-hour visit, again by chewing on a cotton swab.
The time burden will be kept as short as possible, the most preferable time
will be chosen in consultation with the participant. In this case, the
participant doesn*t have to skip any other important matters, like school, work
or sports.
In view of the small burden and the lack of risks involved in participation,
the performance of the research is justified.