Gene-environment interactions and the functional analysis of challenging behaviour in children with intellectual and developmental disabilities.

It is argued that an approach characterised by either genetic or environmental determinism fails to adequately describe the contingencies involved in the evocation and maintenance of challenging behaviors in children with intellectual and developmental disabilities. Instead, challenging behavior should be considered as a result of the interaction of genetic and environmental variables. This argument is illustrated through a conceptual model for the development of challenging behaviour and recently gathered data on differences in the functions of challenging behavior in children with different genetic syndromes. The findings are further discussed in the context of a developmental systems model, in which neither the influence of genetic nor environmental contributions can be fully understood without taking account of the other. This expanded model may hold important implications for the understanding of challenging behavior.