Preventive effects and cost-effectiveness of the Incredible Years program for parents of preschoolers with aggressive behavior

Parenting problems and child behavior problems are being viewed as putative precursors of adult criminal and violent behavior. Moreover, aggressive behavior in early childhood affects daily life of both children and their surroundings, resulting in serious economic implications to society. In many countries, early detection and the prevention of conduct problems have become important goals for authorities in child development and those who provide community mental health services. Hence, intervention programs specifically designed to prevent the development of conduct problems in at risk children have been developed. Since parenting has the most proximal influence on young children’s development, it is not surprising that behavioral parent trainings have been found to effectively reduce aggressive behavior problems in young children. The Incredible Years (IY) parent program appeared to be effective from treatment studies, but evidence for the preventive effectiveness of this program remains inconclusive. The present study aimed to evaluate the effects and cost-effectiveness of the IY parent program for parents of preschool children who were at risk for a chronic pattern of conduct problems two years after termination of the intervention. The IY parent program is a manualized behavioral parent training aiming at the improvement of parenting skills in order to reduce child aggressive behavior. A population based sample of 144 preschool children with a high level of aggressive behavior was divided into an intervention group and a matched control group. The control group received care as usual (CAU). In order to measure intervention effects, a direct observation and parent questionnaires were used to measure parenting skills and child behavior. Results revealed significant improvements in observed and parent rated parenting skills. Moreover, observed negative child behavior in the intervention group was significantly decreased, relative to the control group. The change in observed critical parenting from pre to post-intervention mediated the change in negative child behavior from pre-intervention to two-year follow up, and from structural equation modelling analyses, in which bidirectional influences of parenting skills and child behavior over time were investigated, it became clear that parental influence increased over time. The intervention was most beneficial to children with a high level of initial aggressive behavior. With respect to the cost-effectiveness analysis, cost data were collected including intervention costs, use of public services such as health care and special education, damage caused by the child, travel costs and parental productivity losses. The intervention appeared to be dominant over care as usual; the IY parent program showed better effects and was cost-saving. In conclusion, The IY parent program is unambiguously dominant, i.e. cost-saving and effective in reducing negative behavior. This population based study highlights the potential of the IY parent program as an indicated preventive intervention for preschool children at risk for a chronic pattern of conduct problems