Assessing eating disorder symptoms in adolescence: is there a role for multiple informants?

OBJECTIVES: Studies of adolescent psychiatric disorders often collect information from adolescents and parents, yet most eating disorder epidemiologic studies only rely on adolescent report.
METHOD: We studied the eating disorder symptom reports, from questionnaires sent at participants' ages 14 and 16 years, provided by 7,968 adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC), and their parents. Adolescents and parents were asked questions about the adolescent's eating disorder symptoms (binge eating, vomiting, laxative use, fasting, and thinness). We assessed cross-sectional concordance and prevalence using kappa coefficients and generalized estimating equations. Generalized estimating equations were used to assess prospective associations between symptom reports and adolescent weight outcomes measured at a face-to-face assessment at 17.5 years.
RESULTS: Parents and adolescents were largely discordant on symptom reports cross-sectionally (kappas < 0.3), with the parent generally less likely to report bulimic symptoms than the adolescent but more likely to report thinness. Female adolescents were more likely to report bulimic symptoms than males (e.g., two to four times more likely to report binge eating), while prevalence estimates according to parent reports of female vs. male adolescents were similar. Both informants' symptom reports were predictive of body mass and composition measures at 17.5 years; compared to adolescent report, parentally reported binge eating was more strongly predictive of body mass index. DISCUSSION: Parent report of eating disorder symptoms seemed to measure different, but potentially important, aspects of these symptoms during adolescence. Epidemiologic eating disorder studies should consider the potential value added from incorporating parental reports, particularly in studies of males.