Exploring the behaviour and wellbeing of UK schoolchildren using multi-informant reports

It has been suggested that polyphenols are linked to behaviour and wellbeing. A randomised chronic 10-week, parallel group, double blind, placebo controlled study investigated the effects of daily consumption of a flavanone-rich orange juice drink compared with a placebo on behaviour and wellbeing in 8 to 10 year old healthy schoolchildren (n=32). As the intervention study aimed to use data collected, from multiple informants using measures of behaviour and wellbeing, this thesis also aimed to establish the value of self-report measures in the accurate reflection of a child’s behavioural and emotional difficulties, using the Strengths and Difficulties Questionnaire (SDQ). The tool development work explored the psychometric properties of SDQ data collected from different informants; parents, teachers and the children themselves, in a sample of healthy young schoolchildren aged 8 to 10 years old (n=126). The study found that the internal reliability, inter-rater agreement and concurrent validity of the SDQ, when completed by the adult informants (parents and teachers) were satisfactory and consistent with previous research. The structural validity of the teacher informant data supported the original five-factor structure of the SDQ as proposed by Goodman (1994). While, the parent informant data generated a four-factor solution and the children’s self-reported data produced a three-factor solution, which appeared to reflect young children’s categorisation of behaviours and traits. Overall, the factor structure generated provides valid information about behaviour and wellbeing in children as young as 8 years old. The randomised chronic 10-week, parallel group, double blind, placebo controlled study, then used the tool development to investigate the effects of daily consumption of a flavanone-rich orange juice drink compared with a placebo on behaviour and wellbeing (using the SDQ, RCADS and SNAP-IV) in 8 to 10 year old healthy schoolchildren (n=32). This exploratory study did not find any effect of the flavanone-rich dietary intervention on any measures of behaviour and wellbeing, as reported by any of the informants. Taken together, the research presented in this thesis highlights the importance of assessing the validity and reliability of measures used to assess the behaviour and wellbeing of young children in clinical practice and research. It also provides an indication of how these measures might be further developed for future work in the field.