In addition to the subjective data, we will corroborate the results with the assessment of epigenetic consequences of appetitive aggression and trauma and investigate its significance and persistence in the long-term course of the study. We propose that specific DNA methylation patterns are important markers of environmentally driven mental health pathologies, such as chronic aggression/violence and traumatic stress in such a sample of perpetrators or young males at risk for perpetration. Further, we will test the stability of DNA methylation and its potential modification over a period of up to 25 months by behavioural intervention (FORNET).