Early Prediction of Violence and the Disruptive Behaviour Disorders: Follow-up of the Cardiff Child Development Study

Our aim in the Cardiff Child Development Study (CCDS) has been to identify children who are highly aggressive and have serious difficulties dealing with other children, while taking into account any natural rise and fall in aggressiveness over the first years of life. It is extremely important to distinguish clinically significant behavioural problems from more ordinary forms of misbehaviour and the self-assertion that is characteristic of two-and three-year-olds. Over 300 families joined the study when the mother was pregnant with her first child. During the pregnancy, we interviewed both mother and father about their backgrounds, their health, and their hopes and plans for their babies. We then observed the infants four times between 6 months and the third birthday, during home visits (at 6 and 21 months) and birthday parties at the School of Psychology, where infants met other infants from other families who were participating in the study. Our observations of the birthday parties revealed that, contrary to many parents' beliefs, infants were more likely to share toys with each other than to try to grab toys, and were highly unlikely to strike out at other babies. However, even in the first year of life it was clear that some infants seemed more angry and aggressive than others; infants were more likely to show aggression if their families had experienced hardship, if their parents had a history of behavioural problems, and if their mothers had smoked cigarettes or been depressed during the pregnancy. Their early signs of aggressiveness were reported by mothers, fathers, and other family members who knew the infants well. What the family members reported was echoed by our observations during the birthday parties; for example, infants whose parents had behavioural problems were more likely to strike out at other infants. Infants' tendencies to show anger or be aggressive were still apparent a year later, as reported by parents and other family members. We therefore believe it is possible that we have already identified those infants will have the most difficulties settling into school and who may develop serious behavioural and emoitonal problems. To test this hypothesis, we propose to complete the CCDS by seeing the children again when they are 6 years old. We will visit the families at home and observe the children with their parents and, in many cases, younger siblings. We plan to use a variety of games and virtual reality tasks to measure the children's abilities to solve problems, control their impulses, and choose non-aggressive solutions to the dilemmas created by other people's challenging behaviour. We will also use well-established methods for determining whether any of the children are showing clinically significant emotional or behavioural problems, and we will get parents' permission to ask teachers to report on the children's behaviour at school. We will also measure the children's activity and heart rate to see if biological factors underlie their behavioural and emotional problems. If our hypothesis is confirmed--if we have indeed identified those infants who are already on a pathway to violent behaviour--it may be possible to identify the factors at home and in school that help children control their anger and find constructive ways to deal with everyday challenges. Thus the CCDS provides a unique body of evidence that can inform prevention and intervention strategies to help troubled children.

The primary aim of the proposed resaerch is to determine if infants' angry aggressiveness is a true precursor to clinically significant symptoms of Disruptive Behaviour Disorders (DBD). We shall complete a prospective longitudinal study of a nationally representative sample of first-born infants, in which families were assessed in pregnancy and at 6, 12, 21 and 33 months post partum, with a final home visit at 6 years of age, when early-onset DBD can be diagnosed reliably. We shall use the wealth of behavioural, cognitive and physiological measures taken in the first 3 years to determine if early aggressiveness does predict DBD; to identify processes that underlie the emerging gender difference in DBD; to test a neurobiological model of the origins of DBD; and to identify social cognitive skills and prosocial tendencies that protect angry, aggressive infants from going on to develop clinically significant DBD, even in the face of other biological and social risk factors. The study will provide a unique base of evidence that will inform future prevention and intervention strategies.

Our work at earlier stages of the Cardiff Child Development Study has begun to have an impact on the following professional groups:

1. Perinatal psychiatrists and health visitors: Our initial findings have corroborated earlier research highlighting a link between maternal depression in the perinatal period and adverse outcomes for children, in particular early signs of aggressiveness that are already apparent by six months of age. Hay's earlier work on this topic has contributed to NICE and SIGN clinical guidelines for the management of antenatal and postnatal depression; the findings emerging from the CCDS are likely to identify mechanisms involved, which will in turn contribute to discussions of management and treatment. We have also presented findings to midwives and discussed the need to incorporate information about perinatal mental illness into midwifery education.

2. Forensic psychologists: As we disseminate our findings from the CCDS, forensic psychologists and psychiatrists are expressing interest in our evidence for early precursors to aggression and related forms of antisocial behaviour. We have presented our work at criminology conferences and to clinicians working in forensic services in Cardiff. We have presented our work and begun a collaboration with academic forensic psychiatrists and also with members of the Violence Research Group in Cardiff. This initial communication of findings may open up further channels whereby our work will have an impact on forensic services.

3. Intervention scientists: We believe that our findings from previous waves of the CCDS and particularly the proposed outcome measures at age 6 will be of interest to practitioners who are delivering intervention and prevention programmes. We have presented our work to the Flying Start Conference in Wales and to intervention researchers in Canada. Most importantly, van Goozen is a PI on an intervention study in the Netherlands, which has drawn heavily on measures developed for use in the CCDS. This will represent a direct impact of our findings on intervention research.

4. Capacity-building in the health service: Postgraduate researchers who have worked with us in earlier waves of the CCDS are now pursuing careers in the health service. Two have qualified as clinical psychologists, with three others currently on clinical courses. Three other clinical trainees volunteered their time on the CCDS, and all testify to the importance of the research skills they developed while delivering our research protocols and to the knowledge gained about early psychological development from the assessments made. Other students who gained PhD degrees whilst working on the CCDS are now working in health policy in an NHS trust and as a senior researcher in epidemiological health research. The study has served as a very useful training platform for individuals, which will eventually foster their competence as clinicians and applied researchers.