Behavioural Difficulties in Early Childhood: Findings from a Longitudinal Birth Cohort

Abstract

Targeting behavioural problems in early childhood may be important for the prevention of later adverse outcomes. However, there is evidence that behavioural difficulties may not remain stable during this period. This thesis was interested in investigating the development and stability in behavioural problems during early childhood, focusing on how the family context plays a role in influencing these difficulties. Using the Growing Up in New Zealand birth cohort, behavioural problems were assessed when children were 2 years and 4.5 years using the preschool and standard parent-rated Strengths and Difficulties Questionnaire (SDQ), respectively. This thesis firstly investigated whether the SDQ was an acceptable measure of behaviour at 2 years. In addition, the current thesis evaluated whether behavioural difficulties remained stable from 2 to 4.5 years. Guided by Bronfenbrenner's (1979) bioecological model and focusing specifically on the family context, the predictors of early childhood behavioural difficulties were assessed. Preschool cognitive delays associated with the development and persistence of early childhood behavioural difficulties were also evaluated. The results revealed that the SDQ was a generally acceptable measure of behavioural difficulties in 2-year-old children. Further, it was demonstrated that behavioural problems were not stable during the early childhood period, as the majority of children who showed behavioural difficulties at age 2 improved at 4.5 years. It was found that children who developed behavioural problems between 2 to 4.5 years and children who showed persistent difficulties were at an increased risk of delays in language and executive control. Investigation into risk factors indicated that maternal mental health at multiple time points was associated with the development and persistence of early childhood behavioural difficulties. Parenting factors, such as maternal self-evaluation and harsh parenting styles were also related to the development and stability of early childhood behavioural problems. Distal factors linked to early childhood behaviour included verbal and physical inter-parental conflict, as well as family social support. Overall, the current thesis has several implications for initiatives targeting behavioural problems in early childhood. Most notably, this thesis suggests that a multisystem, family-centred approach is important for targeting behavioural problems during early childhood.