The aim of this study was to use meta-analytic techniques to compare self-concept between children and adolescents (abbreviated to youth) with a chronic illness versus healthy controls, and to examine methodological influences on effect sizes.
Databases were searched for asthma, cerebral palsy, diabetes, epilepsy, and juvenile arthritis. Inclusion criteria were: 1) original research studies in English; 2) youth <18 years; 3) the inclusion of self-reported self-concept; and 4) data available to estimate effect sizes. Study quality was assessed with a modified Quality Index. Effect sizes were calculated as Hedges' g using a random effects model.
A total of 60 studies were analyzed. On average, youth with a chronic illness had compromised self-concept, d = -0.17 [-0.27, -0.07]. However, type of control group exerted a moderating influence that resulted in discrepant findings. Studies based on normative data reported higher self-concept in youth with a chronic illness, d = 0.27 [0.06, 0.47], whereas studies that recruited healthy controls reported lower self-concept in youth with a chronic illness, d = -0.25 [-0.34, -0.15].
Self-concept is compromised in youth with a chronic illness; however, the effect size may be underestimated because of methodological weaknesses and systematic biases in existing studies. Future research should avoid the use of normative data and employ rigorous methods to ensure representative sampling and control of confounding variables to better appreciate the impact of chronic illness on youths' self-concept.