Author: Chloe Fletcher
Fletcher, Chloe, 2020 An exploration of illness perceptions among young people who have a parent with cancer, Flinders University, College of Medicine and Public Health
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This thesis describes the validation of an instrument to assess illness perceptions among adolescents and young adults (AYAs) following a parent’s cancer diagnosis. Five studies were completed. Study 1 was a comparative systematic review of the psychometric properties of instruments designed to measure illness perceptions in family members of those with chronic physical illness. This study highlighted that better reporting of psychometric information was needed and found that measurement of illness perceptions in children of parents with illness had been largely overlooked.
Only one of the instruments included in the review had been validated for use in adolescents (the Perceptions of Parental Illness Questionnaire; PPIQ). The PPIQ was developed to assess the dimensions of illness perception described in the Common-Sense Model of Self-Regulation (CSM) among adolescents with a parent diagnosed with multiple sclerosis. This finding informed the direction of the research that followed, the aim of which was to adapt and validate a cancer-specific version of the PPIQ.
A qualitative study (Study 2) was conducted to determine whether the CSM adequately explained AYAs’ perceptions of their parent’s cancer. Deductive thematic analysis of data from eleven semi-structured interviews confirmed that perceptions corresponded with the dimensions of the CSM. Findings guided the adaptation of the PPIQ to produce a cancer-specific version (the Perceptions of Parental Illness Questionnaire-Cancer; PPIQ-C).
The content validity of the PPIQ-C was examined using think-aloud and verbal probing techniques in Study 3. Cognitive interviews were conducted with four young people. Based on findings, the questionnaire was modified to improve the relevance, comprehensiveness, and comprehension of items.
In Study 4, cross-sectional data from 437 AYAs was used to evaluate the psychometric properties of the PPIQ-C. The dimensional structure of the PPIQ-C was determined through exploratory factor analysis. Test-retest reliability, internal consistency, and construct validity were assessed and deemed adequate. The final PPIQ-C consisted of 67 items across 11 core dimensions (identity, emotional representations, coherence, consequences for personal development, consequences for family relationships, consequences for daily activities, personal control, treatment control, recovery, unpredictability, and chronicity) and three causal dimensions (behavioural or environmental attributions, chance or luck attributions, emotional or psychological attributions).
Using data collected in Study 4, the final study investigated the screening utility of the PPIQ-C (Study 5). Cluster analysis revealed greater psychological morbidity among young people who scored higher on identity, emotional representations, consequences for personal development, consequences for family relationships, consequences for daily activities, unpredictability, chronicity, behavioural or environmental attributions, and emotional or psychological attributions subscales. Scores on these subscales were summed to produce a Total Negative Beliefs score. Optimal cut-off scores for identifying AYAs at risk of psychological distress (137.5) and post-traumatic stress (135.5 for young adults and 140.5 for adolescents) were determined using receiver operating characteristic curves. These findings were discussed in terms of their implications for clinical practice and service provision.
This research provides novel insight into how illness perceptions contribute to psychological morbidity in young people following their parent’s cancer diagnosis. The PPIQ-C has important potential for application in both research and clinical settings.
Keywords: adolescent and young adult, Common-Sense Model of Self-Regulation, coping, illness perceptions, measurement instrument, parental cancer, psychological outcomes, psychometric properties
Subject: Primary Health Care thesis
Thesis type: Doctor of Philosophy
Completed: 2020
School: College of Medicine and Public Health
Supervisor: Prof Carlene Wilson