Differential Susceptibility to Parenting: Gene-Environment Interactions in Children's Problem and Prosocial Behavior

Externalizing behavior problems are the most common and as most stressful
experienced problems in children (SCP, 2006). Both environmental factors (e.g.
parenting, Shaw et al, 1998) and child factors (e.g. neurobiological factors;
Matthys, Vanderschuren & Schutter, in press) play an important role in the
development of externalizing problem behavior. Research has shown that certain
polymorphisms are related to the development of these problems (Rutter, Moffit,
& Caspi, 2006). Most studies however have only focused on the cumulative
negative effects of specific risk genes and a negative environment. Potential
benefits of the same genes in interaction with a positive environment are
therefore underestimated. Recently there is evidence that children with certain
genes, that suffer from adverse environmental conditions, can also benefit the
most when exposed to positive environmental conditions. This interaction can be
explained by a recently raised hypothesis, namely that some children based on
their genetic makeup are susceptible to both positive and negative
environmental factors (*differential susceptibility theorie*; Belsky, 1997;
2005).

To answer the question whether an intervention, aimed to reduce problem
behavior, is more effective for a particular genetic subgroup of children, and
why this might be. The current studie study gives insight into the moderating
effects of specific polymorphisms on externalizing behavior, and behavioral
processes that are underlying the moderating effects .

The study will use a randomized controlled trial (RTC) with an experimental
(IC) and a no-active intervention control group (CC). De effectiveness of the
parent training Incredible Years will be used as intervention (see METC
protocol number 03-119-k en 09-433).

The IY program is a 14-16 week parent training where parents learn parenting
skills specifically tailored to reduce externalizing problem behavior of
children. Parents watch videos together, discuss them, and practice in
role-plays with different parenting techniques. Trainers are not prominently
teaching parents new skills, but are part of the group and guide the discussion
by asking open-end questions and by emphasizing positive parenting techniques.
This way, parents are encouraged to come up with their own solutions to their
problems and will not develop a dependency upon the professionals.

Burden on participants will be minimal. Participants are not at any risk for
injury caused by participating in the study.