To Örebro University

Objective: This study thus aims to test differences between patients with inflammatory bowel disease (IBD) regarding IBD symptomatology, cognitive fusion, and psychological and physical health, as well as to explore whether the maladaptive emotion regulation process of cognitive fusion longitudinally impacts on the baseline and evolution of these outcomes over a period of 18months.

Design and methods: Participants include 116 IBD patients with a mean age of 36.76 (SD=11.39) of both genders (69.83% females) that completed the self-report measures of interest in three different times, equally spaced 9months apart, over a period of 18months. Latent growth curve models were conducted using structural equationmodelling to estimate the growth trajectory of the variables in study.

Results: Inflammatory bowel disease symptomatology and cognitive fusion's levels were negatively associated with psychological health and physical health's baseline levels. Furthermore, IBD symptomatology did not influence the growth of psychological health, while cognitive fusion did (=.30, p=.007). The same result was found for physical health (=.26, p=.024). These findings indicate that individuals with higher levels of cognitive fusion present lower levels of psychological health and physical health that tend to further decrease over the time through the effects of this maladaptive emotion regulation process.

Conclusions: This study implies that it is of crucial importance to include psychotherapeutic interventions in the health care of patients with IBD. If successful, these interventions could represent decreases in the cost of IBD treatment and in the use of drugs with adverse side effects, in addition to improving patients' mental health and quality of life. Further implications for clinical and research work are discussed.