Abstract Background More knowledge about characteristics of children and adolescents who need intensive levels of psychiatric treatment is important to improve treatment approaches. These characteristics were investigated in those who need youth Assertive Community Treatment (youth-ACT). Method A cross-sectional study among children/adolescents and their parents treated in either a regular outpatient clinic or a youth-ACT setting in a specialized mental health treatment center in the Netherlands. Results Child, parent and family/social context factors were associated with treatment intensification from regular outpatient care to youth-ACT. The combination of the child, parent, and family/social context factors adds substantially to the predictive power of the model (Nagelkerke R2 increasing from 36 to 45% for the three domains separately, to 61% when all domains are combined). The strongest predictors are the severity of psychiatric disorders of the child, parental stress, and domestic violence. Conclusions Using a wide variety of variables that are potentially associated with treatment intensification from regular outpatient clinic to youth-ACT, we constructed a regression model illustrating a relatively strong relation between the predictor variables and the outcome (Nagelkerke R2 = 0.61), with three strong predictors, i.e. severity of psychiatric disorders of the child, parental stress, and domestic violence. This emphasizes the importance of a system-oriented approach with primary attention for problem solving and stress reduction within the system, in addition to the psychiatric treatment of the child, and possibly also the parents.