This work deepens the study of the assault on offenders. The main objective was to check whether repetition of crime and institutional disadaptation to the reform centre varied across different groups shaped according to different patterns of aggression. The criminal record and disciplinary offences in the initial period of detention were analysed, and the Reactive/Proactive Agresion Questionnaire was applied to a sample of 184 offenders between 14 and 20 years of age, who complied with detention measures in a judicial enforcement centre in the Community of Madrid. The results indicated that proactive aggressive subjects had a higher number of crimes and subjects with low aggression committed fewer disciplinary offences. The results were discussed, noting the importance of determining the type of aggression for intervention and assessing the risk of violence.