To Örebro University

Research has questioned whether it is feasible to assess psychosocial variables through web-based recruitment methods. Previous literature on IBD focused exclusively on testing differences on psychosocial scores and did not test the invariance between types of recruitment on the relationships between variables. The aim of the present study is thus to analyse structural invariance between internet-recruited and hospital-recruited groups of IBD patients on a mediation model with theoretical basis on previous studies (experiential avoidance as possible mediator of the association between IBD symptomatology and psychopathology). The internet sample included 137 IBD patients recruited through a patients association, and the hospital sample comprised 66 IBD patients. Structural equation modelling was used; a multiple-group comparison was conducted to examine model invariance between samples. Although the internet sample presented higher levels of experiential avoidance and psychopathological symptoms compared to the hospital sample, the relationships between these variables were invariant across groups. Experiential avoidance partially mediated the impact of IBD symptomatology on levels of stress, anxiety, and depression symptoms in a similar way for online respondents and hospital-recruited patients. This is a new finding that argues for the validity of web-based research methods.