Differences in cortisol response affect the distinction of observed reactive and proactive aggression in children with aggressive behaviour disorders.

Various researchers distinguished two categories of aggressive behaviour, namely reactive and proactive aggression. Reactive aggression is an aggressive response to a perceived threat or provocation, whereas proactive aggression is behaviour that anticipates a reward. In the present study, including both a sample of disruptive behaviour disordered (DBD) and normal control (NC) children, we observed reactive and proactive aggressive behaviour during an experimental dyadic play session. DBD children showed more observed reactive and proactive aggression. Subsequently, we investigated whether the observed measures correlated with parent-rated measures of reactive and proactive aggression in. We distinguished in both NC and DBD children a subgroup showing a rise in cortisol level, i.e. responders, and a subgroup who did not show a rise in cortisol, i.e. non-responders. Results suggest that differences in the cortisol response affects the correspondence between observed and parent-rated reactive and proactive aggression since only DBD non-responders showed the expected correlations.