BackgroundAdolescents with externalising problems in secure residential care differ in age of onset of disruptive behaviour and in cumulative risks in several domains. In order to reduce negative consequences of externalising behaviour for society and the adolescents themselves, it is important to gain more insight into the complexity and heterogeneity of disruptive behaviour in these adolescents. To look beyond the influence of single risk factors, the aim of this study is to investigate the moderator effect of co-occurring risk factors in multiple domains on the relation between age of onset of disruptive behaviour and two types of externalising problems in adolescence.MethodsRetrospectively collected data of 225 adolescents admitted to secure residential care were analysed. The four risk profiles were based on co-occurring pre-admission risk factors in four domains, which were identified in a previous study by latent class analysis. Multiple regression models were used to test whether the independent variable age of onset and dummy-coded moderator variable risk profiles had statistically significant associations with aggressive behaviour and rule-breaking behaviour of the adolescents, as reported by professional caregivers in the first months of admission.ResultsRisk profiles moderated the relation between age of onset of disruptive behaviour and rule-breaking behaviour. Adolescents with childhood-onset disruptive behaviour within the risk profile with mainly family risks showed more rule-breaking behaviour in the first months of their admission to secure residential care than adolescents with an onset in adolescence within the same risk profile. Risk profiles, however, did not moderate the relation between age of onset of disruptive behaviour and aggressive behaviour.ConclusionHeterogeneity of aggressive and rule-breaking behaviour was established in this study by finding differences on these two types of externalising behaviour between the childhood- and adolescence-onset groups and between the four risk profiles. Furthermore, risk profiles moderated the effect between age of onset of disruptive behaviour and rule-breaking behaviour—not aggressive behaviour—in adolescents admitted to secure residential care. While respecting the limitations, adolescents’ childhood-onset disruptive behaviour within a profile with mainly family risk factors appear to be distinctive from adolescents with adolescence-onset disruptive behaviour within the same risk profile.