Subtypes of aggression and their relevance to child psychiatry

Objective: To review the evidence for qualitatively distinct subtypes of human aggression as they relate to childhood psychopathology. Method: Critical review of the pertinent literature. Results: In humans, as well as in animals, the term aggression encompasses a variety of behaviors that are heterogeneous for clinical phenomenology and neurobiological features. No simple extrapolation of animal subtypes to humans is possible, mainly because of the impact of complex cultural variables on behavior. On the whole, research into subtypes of human aggression has been rather limited. A significant part of it has been conducted in children. Clinical observation, experimental paradigms in the laboratory, and cluster/factor-analytic statistics have all been used in an attempt to subdivide aggression. A consistent dichotomy can be identified between an impulsive-reactive-hostile-affective subtype and a controlled-proactive-instrumental-predatory subtype. Although good internal consistency and partial descriptive validity have been shown, these constructs still need full external validation, especially regarding their predicting power of comorbidity, treatment response, and longterm prognosis. Conclusions: Our understanding and treatment of children and adolescents with aggressive behavior can benefit from research on subtypes of aggression. The differentiation between the impulsive-affective and controlled-predatory subtype as qualitatively different forms of aggressive behavior has emerged as the most promising construct. Specific therapeutic hypotheses could be tested in this context and contribute to a full validation of these concepts.