LAUSR

Irritable Bowel Syndrome (IBS) is one of the most common gastrointestinal disorders with symptoms of chronic abdominal pain and changes in bowel movements. Although the cause of this disorder is not known, psychological factors have been reported among the most important causes of IBS. This research was conducted to test and compare the structural relationship model of type D personality and depression with the mediating role of cognitive distortions and family functioning in patients with IBS and healthy people. Furthermore, we compared the mediational model across levels of grouping variable (IBS and healthy groups). The research method was descriptive and correlational and the sample included 236 healthy citizens, aged 20–60 years old (130 females and 100 males), who were selected by stratified random sampling method and 236 citizens with IBS, aged 20–60 years old (177 females and 59 males), who were selected by purposeful sampling method. The research participants responded to Beck Depression Inventory-short form (BDI-13), Type D Personality Scale (DS-14), Interpersonal Cognitive Distortion Scale (ICDS), Family Functioning Assessment Device (FAD), and IBS Symptom Index questionnaire based on ROME III criterion. The obtained data were analyzed using structural equation modeling (SEM). The results revealed that the model proposed in this research has an acceptable fit in both groups. Also, according to the results, cognitive distortion and family functioning play a mediating role in the relationship between type D personality and depression. In the case of comparing the mediational model across levels of grouping variable (IBS and healthy groups), we concluded that all paths are not different across the two models. In general, the findings of this study can be specifically applied by counselors and psychotherapists.