UC San Diego

Celiac disease is a chronic illness in which quality of life (QOL) is compromised and psychiatric illness is commonly co-occurring. The only available treatment for celiac disease is to consume a gluten-free diet indefinitely, which is burdensome and costly. Further, adults with celiac disease present with a variety of gastrointestinal and extraintestinal symptoms that can persist after diagnosis and may relate differently to gluten-free diet adherence, psychiatric wellbeing, and QOL. Despite a need for behavioral intervention to address these challenges, adults with celiac disease are understudied. This three-paper dissertation addressed gaps in the literature by (1) examining the factor structure and psychometric properties (internal reliability, convergent validity, known groups validity, incremental concurrent validity) of Celiac Disease Quality of Life Survey (CD-QOL) scores among U.S. adults with celiac disease; (2) examining patterns of persisting physical symptoms and their respective relationships to gluten-free diet adherence, psychiatric symptoms, and QOL using latent profile analysis; and (3) systematically reviewing the design of single-session Acceptance and Commitment Therapy (ACT) interventions for chronic illness populations and meta-analyzing QOL and functioning outcomes to inform future behavioral intervention development for celiac disease. Studies 1 and 2 used U.S. adult participant data from the iCureCeliac® patient-powered research network. Study 1 (N=453) results supported use of the 20-item English CD-QOL as a measure of celiac disease-specific QOL with a total score and four subscale scores (limitations, dysphoria/stigma, health concerns, and inadequate treatment). Study 2 (N=523) identified four unique physical symptom profiles characterized by variations in gastrointestinal and extraintestinal symptoms and subjective ratings of health. Subgroups associated with these profiles also differed regarding anxiety and depression symptoms, limitations due to physical and emotional health, social functioning, and fatigue/sleep, but not gluten-free adherence or celiac-disease specific QOL. Study 3 found support for the acceptability, feasibility, and preliminary efficacy of single-session ACT for improving QOL and psychiatric symptoms among chronic illness populations. Findings suggest that healthcare providers should screen for psychiatric symptoms and QOL deficits among adult celiac disease patients regardless of symptom burden, and development of brief ACT for celiac disease is warranted. Findings must be replicated in culturally diverse samples.