Parental wellbeing and treatment adherence for children and adolescents with Phenylketonuria (PKU)

  • Emma Medford

Student thesis: Doctor of Clinical Psychology


This thesis was submitted by Emma Medford as part of examination for the degree of Doctor of Clinical Psychology (ClinPsyD), in the Faculty of Biology, Medicine and Health at The University of Manchester. It was submitted in June 2016 for examination in September 2016. The title of the thesis is 'Parental wellbeing and treatment adherence for children and adolescents with Phenylketonuria (PKU)'. Phenylketonuria is a rare genetic disorder that causes cognitive impairment unless treated with a strict, protein-restricted diet. Due to the challenges of treatment adherence, caring for a child with PKU may affect parental wellbeing, and many children and adolescents have poor metabolic control. The overall aim of the thesis was to examine influences on parental wellbeing and treatment adherence. Paper 1 is a systematic literature review of the demographic and psychosocial influences on blood phenylalanine concentration for children and adolescents with PKU. The aim was to identify factors that were robustly linked with metabolic control and could potentially be used to inform clinical practice. Findings from 29 identified studies indicated that whilst a number of demographic and psychosocial factors were related to metabolic control, the most reproducible association was with child age. Quality assessment of the studies indicated some methodological limitations, and a paucity of research in some areas highlighted the need for further research. The limitations of the evidence-base, clinical implications, and directions for future research are discussed. Paper 2 presents an investigation of the psychological impact of parenting a child with PKU, the determinants of parental wellbeing, and the association between parental wellbeing and treatment adherence. Forty-six caregivers of children with PKU completed questionnaires examining psychological distress, parenting stress related to caring for a child with an illness, resilience, perceived social support, and child dependency. The proportion of blood phenylalanine concentrations within target range in the preceding year was used a measure of treatment adherence. Results showed that more than half of caregivers had clinical levels of psychological distress, which was predicted by their parenting stress and resilience. Whilst treatment adherence was not associated with parental distress, it was predicted by child age and caregiver perceived support from family. The limitations of the study, implications for clinical practice, and future research directions are discussed. Paper 3 provides a critical evaluation of Papers 1 and 2 and a personal reflection of the research process.
Date of Award31 Dec 2016
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorAnja Wittkowski (Supervisor) & Debbie Smith (Supervisor)


  • Adherence
  • Treatment
  • Children
  • Wellbeing
  • Parent
  • Phenylketonuria

Cite this